oracle 常用SQL语法手册

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Select

用途:

[ zxz Q u_^%k0

 从指定表中取出指定的列的数据51Testing软件测试网%d L)L8F8O i

语法:51Testing软件测试网S2q6M[ e6Z'}P"V

SELECT column_name(s) FROM table_name

解释:

y8C}.v1rZ-e0

数据库中选取资料列,并允许从一或多个资料表中,选取一或多个资料列或资料行。SELECT陈述式的完整语法相当复杂,但主要子句可摘要为:51Testing软件测试网knl.P4T|)J8w?8a

SELECT select_list
P5^}:K0_OJC0[ INTO new_table ]51Testing软件测试网 A"Epf8m ] H!m
FROM table_source51Testing软件测试网/iHQ)vM/\
[ WHERE search_condition ]
.p y)n&{q0[ GROUP BY group_by_expression ]51Testing软件测试网1fEXa? uDx&tw
[ HAVING search_condition ]51Testing软件测试网Es3i.K'} Q)I!DSgM7A"z
[ ORDER BY order_expression [ ASC | DESC ] ]

ENP$uZ2@+@5k0

例:

"]^7~Pk'D_b9h#B0

 “Persons”表中的数据有51Testing软件测试网*[*u4K$LV-afZ}``

51Testing软件测试网 T*l,_ P X"`o1eT

LastName

Lj/[L*o`9Q&]P0
51Testing软件测试网x,\ Kw yT t~,M

FirstName

L8W N w\8v-k;d0
51Testing软件测试网:RvCf?&i

Address51Testing软件测试网/E{0J\$Vw

*r L7V9Eu1K0City51Testing软件测试网f#a6Z1G-S#rM

51Testing软件测试网2vyuc&y"\w

Hansen

?Y0d0K!V*Ys0

y{k)K{J9X{:S0Ola

IKCca:F ?!T s0

4p5~/_WY0Timoteivn 1051Testing软件测试网DgyQo+a

4Y W6q#k@~0Sandnes

UXQ%~t)`*]9}0
51Testing软件测试网-Jk:IU*^:o2s9i

Svendson51Testing软件测试网|v[W6{/g.Y

51Testing软件测试网`&](OxL6x*DX

Tove51Testing软件测试网H!G rN&{V2w0OP

51Testing软件测试网i6opX5`

Borgvn 2351Testing软件测试网p5r'H;Rz

51Testing软件测试网@$lXDz-s!I&x)Z/m `

Sandnes51Testing软件测试网-AUF;`9?Jr&[

hqS d,g4R8X6a0Pettersen51Testing软件测试网rg#Ssu ~d6A;k

Mu/CJp#W2d5T,p0Kari51Testing软件测试网3J2El2Zg

\U4F!JG^3A0Storgt 2051Testing软件测试网'n3ct B*Gk3U] d

51Testing软件测试网.R;z.kq4o5b}R

Stavanger51Testing软件测试网9m[o i:x

选出字段名LastNameFirstName的数据51Testing软件测试网"uF8?LK,IA4I

SELECT LastName,FirstName FROM Persons

返回结果:51Testing软件测试网[ Y(m;^D+C

51Testing软件测试网Ku`#t``yS7J;z(|

LastName

2m|&e4F.l5j$s6Na7h0
51Testing软件测试网:}qn&RN'wD

FirstName51Testing软件测试网&N IN T"C-f7GN(y

51Testing软件测试网y3b+b\[ etC

Hansen

B&d$e!Ha,AZ4|'xh0

|)E A"c wvq!DQ0Ola51Testing软件测试网+h~5j;Q y,bF9~

51Testing软件测试网MCSP(c |L

Svendson

8Uv%o;D4D{ L0
51Testing软件测试网 Y;w5h{\#dZ#j x

Tove

9uFA \;CW6w|1T0

$D [M_ S"W0Pettersen

hU u-P]gC0
51Testing软件测试网'Fv1| xp;M#|3p-}{M-w/g

Kari51Testing软件测试网(s8UXXj:T

选出所有字段的数据51Testing软件测试网1l!\^-D?4|&A

SELECT * FROM Persons

返回结果:

qv{7])G r4{[;HU0

5F4To{b1U0LastName51Testing软件测试网h7Q1a)qjJP

}cgc!fe#CT0FirstName

8w@5]2|K` hv0

L#q4t"DIV*TecD0Address51Testing软件测试网D }~ a4?]/X![ IU6} V

51Testing软件测试网5?5x!?d|lT4V[#`

City51Testing软件测试网tG9w f7P't)H3UA

9Fcn| Z0D0Hansen51Testing软件测试网\2?3b7E){t"s-apa

51Testing软件测试网9o rw~9M(R~x

Ola51Testing软件测试网#H{@-Yf6E9HZ

&jw}^ p0Timoteivn 1051Testing软件测试网%HJRS!z"T!i$i

]t6e!n6jGyW0Sandnes

$my%?:wH#@7^r2O$r2i0

N4~3i g$hL0Svendson

;C$K)JD V![V0^-y0
51Testing软件测试网 U2YH{qIEH

Tove

5{j!q;`N@ tf0

Kq5{pr4LE(h[0Borgvn 2351Testing软件测试网0DZS8{M2@1p)I

51Testing软件测试网mc\H h"i5Q

Sandnes

g}5}Qy8z0

T y M.lV9n @0Pettersen51Testing软件测试网:}]3w%h+p0{|!kD

51Testing软件测试网{r7w/jBzIC

Kari51Testing软件测试网M n @,Q9sbn3t

u8eHNZwc0Storgt 20

%{'ysb_#~0
51Testing软件测试网~7A s+yS8?I'H

Stavanger51Testing软件测试网+pd LC2S

Where

用途:

f*Z![Q!n/g/q \0

被用来规定一种选择查询的标准51Testing软件测试网1W%E+|,j k3_

语法:

PrNP izB:T{n0
SELECT column FROM table WHERE column condition value

下面的操作符能被使用在WHERE中:51Testing软件测试网*Vq;g-|C\!w#Ycv@ `

=,<>,>,<,>=,<=,BETWEEN,LIKE

*t+y,^"]%[0

注意:在某些SQL的版本中不等号< >能被写作为!=

-u j b)W5h4a9Q0

解释:

,nx#CM;VF0Bk0

 SELECT语句返回WHERE子句中条件为true的数据51Testing软件测试网d,Z-E7m"Qm0QuX3E

例:51Testing软件测试网 cF*X3qC y

Persons”表中选出生活” Sandnes”的人51Testing软件测试网mEWz%Dl

SELECT * FROM Persons WHERE City='Sandnes'

 "Persons"表中的数据有:51Testing软件测试网 }E+^N#I:h

51Testing软件测试网4NC9`"H@7y4zU)mz

LastName

kJ{;NFFb] `0
51Testing软件测试网9}LU2j.T-~

FirstName51Testing软件测试网w6F*jW$a"@C

nY;}Bd)MU0Address51Testing软件测试网 ]n*qP7O.aW.{/M

51Testing软件测试网W1D:B-y nU

City51Testing软件测试网*}bb.Oa/x'LJ

51Testing软件测试网mw w,C,{S H7^,}

Year

Ij;av8j+{,KQ'E0
51Testing软件测试网w:bR~*r0v _(Py

Hansen

lN&l:HTTM `2pS8v0

/MT Csn9I0Ola

G o!^$|8~/Tqsz8^,T0

s@1`3w S'_;?4g0Timoteivn 10

O[ o-h/o}0
51Testing软件测试网?a+UO([d`

Sandnes

[#Yoj)[)S1^ h0
51Testing软件测试网oL6z9HJB?f

1951

X"I%p0l5G^:C]J0

"c4`4?_:n9G+O;S5^c*l {0Svendson51Testing软件测试网F$?0Hp#cf [_

51Testing软件测试网P/BK-nyzX a1n%L(?

Tove

hTGI:~w0
51Testing软件测试网T _ T7Shp9}

Borgvn 2351Testing软件测试网4D4K.A(uU+}^

B#L;d F'LA3J0Sandnes

!r^y` u:U0

}}&e1Q ? Oo$Vx y0197851Testing软件测试网T+fow3Qe

aW-|["a5vQ0Svendson51Testing软件测试网,b#oBiP3lHV}G r

1Q9z'SO0Vd&d-V([0Stale

'k-H$m2ROK-V0
51Testing软件测试网r%q1w5fp(xb

Kaivn 18

MD1E3S#}/b$A;}O'M0

/~@ v Nzm st0[tL:i%ME0Sandnes51Testing软件测试网e1gx6E `(u t

51Testing软件测试网xU9@ JB2J#\*L

1980

]c @~OG7I4\"\kg0
51Testing软件测试网.s@*h;`3S/bK m'i

Pettersen51Testing软件测试网TqN {R:} D P/u

51Testing软件测试网/m qDh4|1BWg

Kari51Testing软件测试网@:F H:Po r

N2z nMB({Lg|F0Storgt 20

H'B/D/j8f(J-a0
51Testing软件测试网~1m HEz5oA

Stavanger

2C|oo | p)rt`Sm0
51Testing软件测试网6B4S(g\ _!u

196051Testing软件测试网Z6LvR0j:C

返回结果:51Testing软件测试网zw7^Ee f1y H

1d-i0I`)d0LastName

8cHhPTM0^;\2iW0

5MxR,j9f9J0FirstName51Testing软件测试网Y?.O0[V] r

Nfk:G]0Address

{+e0|F md4PC%G0

*]/BN#m!D @4Wq3wY0City51Testing软件测试网R9Vf2S\

51Testing软件测试网,iy7o&ce`3K2g7H

Year51Testing软件测试网$@c#o.R{p

51Testing软件测试网)M'lj;vmV!dY

Hansen51Testing软件测试网@(s5w],L V

[D!Ej6HC[0Ola51Testing软件测试网1V5t2Ag'KX|

51Testing软件测试网*|WZ5\+l0L(r1{:M

Timoteivn 10

vm6b3xcf/` Y0
51Testing软件测试网7E5r"{XUV1wT

Sandnes51Testing软件测试网-W"L-T"Dj [*Z"pg,Zn

FkC [XUU#F0195151Testing软件测试网._|Te:`_

51Testing软件测试网!y5d~,DZ;Dw

Svendson51Testing软件测试网W"NuwZ ZN1t]w9O-_

!fq6N4S(a%l3B0Tove

;T} Y(a)Q}$Yx.R0
51Testing软件测试网9e/bBLYTu{&v

Borgvn 2351Testing软件测试网)]? U/UxR6?2W*H

w3p~'Q;y`x0Sandnes51Testing软件测试网z DC{$?r3Xy

51Testing软件测试网M(Z/j^ON z

1978

K/^#p m1ZhRXE0

1x?U1Kj zZG0Svendson

uw~PcL)c0

;dn"adQ4w;Nja0Stale

pC%b6QP!fT-i$x:c'K-F0
51Testing软件测试网l;{ox8K

Kaivn 1851Testing软件测试网Z Ja.NMWd8b!i/?_}

F#e Q rb-C0Sandnes

u\$E Dz)Pw)jX)D bW0w0

_i2u-A v0198051Testing软件测试网 Nt*aF`0v

And & Or51Testing软件测试网 V-I(L1Z6e/Fs

用途:51Testing软件测试网 A:cC'w}

WHERE子句中ANDOR被用来连接两个或者更多的条件51Testing软件测试网%sk~-B4dgtJE3H

解释:51Testing软件测试网2I,C%a;BF_)}

AND在结合两个布尔表达式时,只有在两个表达式都为TRUE时才传回TRUE

HLb^5W0

 OR在结合两个布尔表达式时,只要其中一个条件为TRUE时,OR便传回TRUE51Testing软件测试网oj+bx8h

例:51Testing软件测试网-u mnt C!p

 "Persons"表中的原始数据:

51Testing软件测试网gp0\~e7u

LastName51Testing软件测试网 r~&e F{gDv_

?-~A%\M{H2D|0FirstName51Testing软件测试网(e4~+q4? B9H}

51Testing软件测试网 d1B)O4\4mk6W

Address

JC k;qU+q;E+w9nJ0

f:oS1l'qG @Fz7Bq,W0City

&{*@)J&@!\ab O0
51Testing软件测试网e7L7X,`;n

Hansen51Testing软件测试网uxMR;bZ NPzL

uKa4D+G%L0Ola51Testing软件测试网}S_4p#x.i1~JG

N3QwP aFZ-C0Timoteivn 10

IXlGS$s0
51Testing软件测试网4lU-fWwy

Sandnes

H]%G.pW,J;C0

*V0d b8T4lz9I0Svendson51Testing软件测试网8r.R-lLc

pm$u`'{^n8fH(JiM0Tove51Testing软件测试网,\in%v2Zbb^4\&v

51Testing软件测试网9a7eq'r3X!i t

Borgvn 23

4p5E:b@3t0xu2Q.n0

^7Lo]$pLdlB5jW ~0Sandnes51Testing软件测试网,hPfW0@_&U8Y

51Testing软件测试网|A er;S

Svendson

"R't D N+|m x0
51Testing软件测试网5[.R#W` P2}+d(vk6W7D

Stephen

IT/j4o-[~)D'k0

dnWt)s u0Kaivn 1851Testing软件测试网7wu!D1[2?5Rt:}"h

51Testing软件测试网 E{w7Ssy[5z/j

Sandnes51Testing软件测试网h jZv{ o vb

 AND运算子来查找"Persons"表中FirstName”Tove”而且LastName” Svendson”的数据51Testing软件测试网9c~.BP8F `{/e

SELECT * FROM Persons
WHERE FirstName='Tove'
AND LastName='Svendson'

返回结果:51Testing软件测试网2DE+h(h g:h8R

51Testing软件测试网0OXwe$fs9z/X

LastName

)sqd%ka4ln0

/[%m I(`!E!f-p1l0FirstName

{2jIpFt1Y V0

)O}XV6y(i!z0Address

G^`"m} Hhw9lp0
51Testing软件测试网"sQ(or;R2q(X9M

City51Testing软件测试网P%C9s ^J7d4gQ D[ }

g:X,E!MFS.W"QR0Svendson

XfT3H.Yb#f0
51Testing软件测试网Yxb:XG{ f

Tove51Testing软件测试网n$a:Inx'Ib

"SlOS3[ n?0Borgvn 23

8k6\m0q0[ee0
51Testing软件测试网(GKf?1y4v

Sandnes51Testing软件测试网7^f9lB#FnQY

OR运算子来查找"Persons"表中FirstName”Tove”或者LastName” Svendson”的数据51Testing软件测试网*o\o'o:mWa

SELECT * FROM Persons
WHERE firstname='Tove'
OR lastname='Svendson'

返回结果:

'g:U1QW~Y/E0
51Testing软件测试网w0[q5Y5T4sH OV

LastName51Testing软件测试网W5O6Nta9] j9E0g5~

4P6p6xD l0FirstName

#@zN9eQ]I2B0

1D"~2p8A;nH r8^)]5p0Address

2g&BAT v1~9W(A:M0

VQUdt0City51Testing软件测试网cJwo(?!vm|9`7V

51Testing软件测试网4ls-Ecp3i)K.p.c:T

Svendson

`oCI]4Pg0i0

i Jh&xm W0Tove

9l)l9V*X/gA-M0
51Testing软件测试网s.r j ~| d,Z-DH)F

Borgvn 2351Testing软件测试网$n1}j/P-A/wd(e?

51Testing软件测试网+u~ RFXI![/Y7aHA

Sandnes

s _r^.s+LBZW8T0

R-V|,PzL)ey0Svendson51Testing软件测试网E(g;I-i3~Uq`s

51Testing软件测试网]sM6w_/MG

Stephen51Testing软件测试网8B]!HR9Svn7E0x4q;H

51Testing软件测试网RQN}!I7|

Kaivn 1851Testing软件测试网'F"c9v)@`"W#WB6a:@4j

9D0E6zx~5}t"H%T|&l0Sandnes

9s-uVm-qDl0

 你也能结合ANDOR (使用括号形成复杂的表达式),:

B?4Z q P\0
SELECT * FROM Persons WHERE
(FirstName='Tove' OR FirstName='Stephen')
AND LastName='Svendson'

返回结果:

I3V1}j8~"M9m/^(W0
51Testing软件测试网 KdQ+C\jT0[

LastName51Testing软件测试网"ia_j@y D+_*}:^

51Testing软件测试网 O+v7L'@;U _ @U:_

FirstName

qrm`vz4{;e0

X,z(BPC'X0Address

&r0^"?l;}9m0
51Testing软件测试网l9O1A ?!B E4u

City

,LeG&aM,r0

d_;jr$^WDH l x [0I0Svendson51Testing软件测试网 jV K&iyR Z;So/T

51Testing软件测试网1R6n(o \ @

Tove51Testing软件测试网uE5p f Z G

51Testing软件测试网cLX8K y(h7?D

Borgvn 23

h D ^/y+B/j\"}x0

0URTF2qiM~0Sandnes

hok*w,Qi,R0

D R5UQ7j#vV"e0Svendson

([F1R8X,V ~;|0

A1A U6?#|0Stephen51Testing软件测试网6vWo?3Z)V

51Testing软件测试网 eUJg } y&H$q

Kaivn 1851Testing软件测试网c c.\.c)U { H

51Testing软件测试网&MJ5V ET

Sandnes51Testing软件测试网`6Cvb z3U/}

Between…And51Testing软件测试网G4|n vSJ8a

用途:

;IU,c Fl[}?o;d:\+m0

 指定需返回数据的范围

%_]JoHJ0

语法:51Testing软件测试网+y a1h@!_;@Q {&D

SELECT column_name FROM table_name
WHERE column_name
BETWEEN value1 AND value2

例:51Testing软件测试网 ]%o9?du

“Persons”表中的原始数据51Testing软件测试网"Io"f8Q.P0vvi ]

51Testing软件测试网 i&e+b7Y2ICm

LastName

5E-Y `Kl'bM q0

1] T{2NJ(Ha/^0\ND8j0FirstName

j)R iI&p*Z0
51Testing软件测试网P,M0pB v

Address

)WK8z1Tu.?G0
51Testing软件测试网q&|2T-f o p4{"d(X

City51Testing软件测试网%[1b(l c`LQ}f5a X:I

51Testing软件测试网uI p[?Y+S;vs

Hansen

'C ?4R}X-\0

'EbE1||,D-b/h0Ola

!Lz[ MUQ*e0
51Testing软件测试网M {l?'A+Ri!K

Timoteivn 1051Testing软件测试网6dkdA ]&~)v

51Testing软件测试网#w u"U,h$[i%{Q2v-b6i

Sandnes

e`KDU ~ y0

"v/D hrc x*UOh0Nordmann

5bJ8F bP@,HbKc0
51Testing软件测试网 bn"|0msU(Lre)W

Anna51Testing软件测试网 Z J;oEF

51Testing软件测试网v:Y(z|5D:YXm

Neset 1851Testing软件测试网6q1j/q1OJ(oPze

$w9s/VRPm-P0Sandnes

v/V-yh y @dOi*Q0

VpP DlDV0Pettersen51Testing软件测试网/^3U#x"H8wu%g

] Bb$p2x8cR7m3j,j0Kari

,rK0Zw+g5{O0
51Testing软件测试网 YJ*P XG[8I c9?-D

Storgt 2051Testing软件测试网Y!p h:{zP

51Testing软件测试网`:j-`R @ Fe

Stavanger51Testing软件测试网f)Qm(CCDbs

/M j;~h+jE-qF0Svendson

-@hD Vk,U V0
51Testing软件测试网+fY dLh(O

Tove51Testing软件测试网#u} d/m5L2t"P

X2E.vwJ;} c0Borgvn 2351Testing软件测试网1}!k*|;B1ul[*`7T j~

51Testing软件测试网*?t&c z'i/D]p

Sandnes

E-r%Id/\H0

BETWEEN…AND返回LastName为从”Hansen””Pettersen”的数据:51Testing软件测试网S#ME4s#vm2a

SELECT * FROM Persons WHERE LastName
BETWEEN 'Hansen' AND 'Pettersen'

返回结果:

ADkb*kg0

hN G+p$x-L4n0LastName

!O3x'B~_1T Jp0
51Testing软件测试网.p#n vO$A,?MY"q7H

FirstName51Testing软件测试网c8S n D7]W Q

0~+r8D1\*P W*`0Address

&fy;c7XUo@R ?3l[0
51Testing软件测试网Y6Z'U?7]F

City51Testing软件测试网h%W NDJ d|oj

51Testing软件测试网 b4i YB9c$[E&Fe'D

Hansen51Testing软件测试网6D$} DJ,_ } v

J0bm'?|)Y0Ola51Testing软件测试网m(fa8K\]@T,l

51Testing软件测试网f|v)YNe

Timoteivn 10

M z%{p\ G0
51Testing软件测试网)G$L*T@P H e7DOt

Sandnes

%R"a&nxH YQ/e0
51Testing软件测试网c1|f5?v'@~5\#^-r8H$k%{

Nordmann51Testing软件测试网 RU)|c X9}

h*I%c(dBe ]0Anna

'\o0P4~e5x;YnW0

Cy&]$`W(_nv:D0Neset 18

`'S+B#e8^]0
51Testing软件测试网.K$]\*|+v3r,E

Sandnes51Testing软件测试网ESx;CF-y

pw6QS @R'u0Pettersen51Testing软件测试网w J Tis s Il

51Testing软件测试网{6M^?6o fH

Kari

5_\c,`-U0

WF,f,N ull5LJ0Storgt 20

G |P`!]}0

5s%PB-n~X(P(G7U(c0Stavanger

s-`5x}3y7lt0

 51Testing软件测试网E!NKMrn*qG

为了显示指定范围之外的数据,也可以用NOT操作符:51Testing软件测试网k @\,Q u C FA

SELECT * FROM Persons WHERE LastName
NOT BETWEEN 'Hansen' AND 'Pettersen'

返回结果:

5LO.](JS+bP^ P0

8h)?,FN'}hf+eqo0o0LastName

cljS2X0
51Testing软件测试网 @BG jQ,X ej

FirstName

g5G8F*As)@ L6q:r0

A/}%H'@.|Z-v0Address

&pq | iJb0

%|^0W,[6K:N]n2@hP0City

iL}V A0

^M#I }$ZJw c0Svendson51Testing软件测试网Dr#\:O'\S*Z

51Testing软件测试网.dYa c8n2HS,@

Tove51Testing软件测试网q0x;TO:K_$?

51Testing软件测试网[8wo3z C0EK

Borgvn 23

;aYy'l&kN0
51Testing软件测试网&}(yb.@H

Sandnes51Testing软件测试网l~{ WCjZ

Distinct

"K~#l2t i {0

用途:

-Qc7|{&jA0

 DISTINCT关键字被用作返回唯一的值51Testing软件测试网8f dW5ZOeu+C

语法:

)@,MX xf%[,}0vK0
SELECT DISTINCT column-name(s) FROM table-name

解释:51Testing软件测试网&H:h;mFVcT

 column-name(s)中存在重复的值时,返回结果仅留下一个51Testing软件测试网2J/uc9^pi {

例:

6?[F.WrD%V0

“Orders”表中的原始数据51Testing软件测试网:f.Vj?p

(@J9?&S0k8[0Company

Z0mFx+T_1hj0
51Testing软件测试网m^ TY%QZ/M"G

OrderNumber51Testing软件测试网1ASTstPs

51Testing软件测试网k8J;g-EL\C'd

Sega

$sqYD ];f&s0

Cu)S:^0zp%~0341251Testing软件测试网`/`p/rRBLd jE

51Testing软件测试网.I\F;N!S-r

W3Schools51Testing软件测试网grR!nJ&O

51Testing软件测试网ud%ou:v%qMy

231251Testing软件测试网n]Bj-^lX}

51Testing软件测试网P3{4iz'I

Trio51Testing软件测试网Y-g q4J b:Q:bX.Oav

51Testing软件测试网-~C7Z)a [ }P!]hM

4678

#LN8E|}&}0

#w&cGw5gW0W3Schools

!}:j\$svY8mX"]7l0c0
51Testing软件测试网WpV:b0i*j$k1U

6798

P"@N#\&N\j'S0

DISTINCT关键字返回Company字段中唯一的值:51Testing软件测试网R&Q9Jp,l'z*c3Sq&d

SELECT DISTINCT Company FROM Orders

返回结果:

j%R4B3H"z~0
51Testing软件测试网1Ny-BXqh2u1\ z x.O

Company51Testing软件测试网SDh$^,@9n{:E#JV

51Testing软件测试网+} @^pn3M

Sega51Testing软件测试网'E`0C/^9V ~@

51Testing软件测试网O+Fv*^dF%I!G

W3Schools

*` S_WzI-Xos0
51Testing软件测试网 z i#Nad,u] j

Trio51Testing软件测试网9^Y6dQ9UPydr

Order by

9a(FSk"z!`*Y0

用途:51Testing软件测试网R!f@K0L&g5yJJ

指定结果集的排序51Testing软件测试网(sQ)N l I)rq

语法:

O3_5~'Q7@(s+C0
SELECT column-name(s) FROM table-name ORDER BY{ order_by_expression [ ASC | DESC ] }

解释:

jL)|I-j;O2WK0

 指定结果集的排序,可以按照ASC(递增方式排序,从最低值到最高值)或者DESC(递减方式排序,从最高值到最低值)的方式进行排序,默认的方式是ASC

0M^le,|sGz!_0

例:

(n9V/z1B"uV8f ~0

“Orders”表中的原始数据:51Testing软件测试网1c u(\[_,e8u n

(f3C9uNe)j+Qh0Company51Testing软件测试网'j1whu.LI]

51Testing软件测试网4E My;|x[&]J

OrderNumber

F/E/QFS!R Qw0

}C,lB*S)m#z0Sega51Testing软件测试网t d D@l3b

XM(xlS q_U0341251Testing软件测试网F'^tAr2v

|l:dyZrI1cJ[0ABC Shop51Testing软件测试网T1XE9Ze q*E

51Testing软件测试网)y)m)z4J1S"F&g1F$c~

567851Testing软件测试网K i'ioU"b

51Testing软件测试网$`\5C bis|!a

W3Schools

%S%I4Yth sW0
51Testing软件测试网7IVxqP#yq

2312

:F|GR!B s0

E;uN:Mv4v;pZ,U0W3Schools

,Hg/F,Ib;TCWL"[0

I!N${{c n\p_/R0679851Testing软件测试网Xf_+Mt|

按照Company字段的升序方式返回结果集:

p `9kEI4I0
SELECT Company, OrderNumber FROM Orders
ORDER BY Company

返回结果:51Testing软件测试网-o5n(]$igY |&F k/c3e2|

npvYB+o:l:e Uwgv0Company

7~3v f$x].x;j:L5I@0
51Testing软件测试网ky/IT \JIH}6IP1W

OrderNumber

@qa*yDC0
51Testing软件测试网 D!r$R R"] Gs#c e*Z5]

ABC Shop 

!i db[)|*CE6m0
51Testing软件测试网IcS;uxg'Fm

5678

SJ,hm%_tb0
51Testing软件测试网 jS%fkmU }L+S_

Sega51Testing软件测试网R:k ].o#W@

ObNR3w03412

F3L$_#r2R8CP&}0
51Testing软件测试网w }hkoz3n

W3Schools51Testing软件测试网)|tYMd"E

)u'beN0fP-zT0679851Testing软件测试网.v"D9~v/d.{2}9[

51Testing软件测试网-QvK jzpY

W3Schools51Testing软件测试网 hKx,GD1Axe[4}m`

t&o#g utb_02312

C:auf8u7Pg Q0

按照Company字段的降序方式返回结果集:51Testing软件测试网,Ld&qE2r0]2yB(~&O:G

SELECT Company, OrderNumber FROM Orders
ORDER BY Company DESC

返回结果:51Testing软件测试网3I R4V ?H o'f#x

51Testing软件测试网K~B-Nj9N6}

Company51Testing软件测试网*f'@ F[ T1Gb4M,w

51Testing软件测试网 S'H+ij%BRJ/g:\

OrderNumber51Testing软件测试网 J S,] t,eQ7i

/FsR z3uH n|0W3Schools

SP/P*K M/\)E0
51Testing软件测试网 G9p W#b.z(t*Y"}{

679851Testing软件测试网!ta4|bK!j^2h [

/Z}2I \cB0W3Schools

"`5H-P8WG#uk4W J2V!W0

\&[NJyt02312

&ni&vqm'i&v G0

'OU*s#[MA0Sega

Uy{`s1pL0

#q)]8y e{1Qtt5g.]0341251Testing软件测试网w T&?3a Y;q

R/CwDnj,jin0ABC Shop

'ZJnSNl0

QCU/}^0~;}[ r05678

1z1mH @#R}@"L~7p9F0

Group by

y*kQD)r;r|0

用途:

C-kd QJ]C0

对结果集进行分组,常与汇总函数一起使用。

KxwHP&UQ0

语法:

8jBh.Z!m0
SELECT column,SUM(column) FROM table GROUP BY column

例:

:k&r8TsBJ'o}0

“Sales”表中的原始数据:

:LX4L Kv$m7C3^0
51Testing软件测试网~+no+?9p

Company

_z%f9`H6o?7~w0
51Testing软件测试网(h2Q1e"uw'C$l*k\Ir

Amount51Testing软件测试网5E }0q4k:Qe k Cjj(]

#[M){ T\/W;O[1?:E!?0W3Schools

N"LO9D:Nzo-d jR p0
51Testing软件测试网C.M C:Z5b:m

550051Testing软件测试网R4d Zo.I.o+T2s`0C

1Eo3R'I"_O&mYE0IBM51Testing软件测试网!X'A6f+MP/c_

/pN Tp [)E%tr04500

V!b;Z'u;RO0
51Testing软件测试网#z} M? urQ

W3Schools51Testing软件测试网G-no'oZ

qX^mA Xm-M[d07100

,a+Yj*GXb$h:J.WT0

按照Company字段进行分组,求出每个CompanyAmout的合计:

!^?6E/L{i7dI] {0
SELECT Company,SUM(Amount) FROM Sales
GROUP BY Company

返回结果51Testing软件测试网#Lj bz2r Z?J

51Testing软件测试网U'c+fnU

Company51Testing软件测试网?'~Kt%Naa@

Q0n+cU8Q {*a0SUM(Amount)

iP+@N%Bz0
51Testing软件测试网1O/B@#Wgei

W3Schools

R i,dpA0
51Testing软件测试网&s2A0Re:W-@f?0z/U;R

1260051Testing软件测试网-G|r7? uj:q~/F1h v

sZD W;o)g0IBM

ZJd3`stI){"w0

7m3B Z]3Z(m2?04500

5jWe_+R^k8qo0

Having

2p B`]{})K \G0

用途:

o6]V3o+EM IQ!cq0

指定群组或汇总的搜寻条件。

9] F,i/mS:jYd8_G+N-Ku0

语法:

-R5KH3B2y`;t@0
SELECT column,SUM(column) FROM table
GROUP BY column
HAVING SUM(column) condition value

解释:

aZk|2Q:V0

HAVING通常与GROUP BY子句同时使用。不使用GROUP BY时,HAVING则与WHERE子句功能相似。

*L.k8r7m [3@o0

例:

~+oh!kD0

“Sales”表中的原始数据:

JPa4wI+a8DX$m0

L:oG(hK7NcY#P0Company51Testing软件测试网Ph-\DgNrMJ4a,p

'[,`'iY J4x^0Amount

c @i7OLt5Q-YW.]0

uy&ZH SCV V0W3Schools

%ymx\Ci%f{?+g s0
51Testing软件测试网,? Q$ZE1l_1`

550051Testing软件测试网*V9X/V c_(`MdE a

iKzW JMsg*M0IBM51Testing软件测试网R0yfsPu

#K~?+BU/i\0450051Testing软件测试网s-[.s&WM._\

u)F:m"v"io0W3Schools

"@o1~yig2mQ|9M0

*GA`2sQw N0710051Testing软件测试网.Z!K"Tw3|X&E},|g

按照Company字段进行分组,求出每个CompanyAmout的合计在10000以上的数据:51Testing软件测试网)kdN1m |

SELECT Company,SUM(Amount) FROM Sales
GROUP BY Company HAVING SUM(Amount)>10000

返回结果51Testing软件测试网4d([l2{4^\

51Testing软件测试网5SmW#H ^M

Company51Testing软件测试网4mEK$B;i*H y

}!z2CNUQD0SUM(Amount)51Testing软件测试网~J"GgQ)fj

qkTaE-gu3W0W3Schools

x@$SFD1t E!u5H0
51Testing软件测试网%Yc!xhH j2Bu

12600

xW2N)`]H$i'u"E0

Join51Testing软件测试网mp2VI|z U8Yq

用途:51Testing软件测试网!oq-]"R&W2|}M-L

当你要从两个或者以上的表中选取结果集时,你就会用到JOIN51Testing软件测试网:]5Z8M[tRO

例:51Testing软件测试网#\H$o(yf\5IF+E

“Employees”表中的数据如下,(其中ID为主键):51Testing软件测试网U/YDfc,Gw6[,p8^

51Testing软件测试网P$UA'sN&e.R

ID

'iY"C5^@:I;Q0
51Testing软件测试网 m*Tl8VV]x

Name

k.{i7ZW"Am0

cxZ5i"l4k1c00151Testing软件测试网p2{] [8?W&YWD

51Testing软件测试网#c4{9D3{e

Hansen, Ola

NA/M8?N0
51Testing软件测试网 a(c:wtobJ

0251Testing软件测试网 K9o;S9\"D

51Testing软件测试网E6u`0zv U[:il

Svendson, Tove51Testing软件测试网7W2Bh+E;l

-d*W)}z4J8F7RH!H@!?003

N/@4C.SPQ;Pp0

B"wlsr.v6J0Svendson, Stephen51Testing软件测试网U"u!p8s m/M*Mn

Y8u2dL k8Pp~0d&~5N004

a#nr4Y2EG0
51Testing软件测试网1u sH K,F*Hs

Pettersen, Kari51Testing软件测试网CB9i,YK~

“Orders”表中的数据如下:51Testing软件测试网)[:@DHy(zy

51Testing软件测试网5@4B2Q g ~ af2^tf

ID51Testing软件测试网X NO'u)l(ySz

F"~?%RG"q8V0Product

3voeS:zZ K0
51Testing软件测试网 sT?0j \a&{!w&F

01

dj NI(|"?1?f `0
51Testing软件测试网/ru3Lz z(a

Printer

#r&A1Iw K0
51Testing软件测试网*u%a4s)_(N`

0351Testing软件测试网/V#f%FJ7?j4]

51Testing软件测试网m&I~;P n2B

Table

^BJX}Q5So0

3x2kY n"G0f7k(J"A00351Testing软件测试网"n is#Z+|A

py#\/B0S i!F8g0Chair

^4O%P7i$x#A?+k,s f0

EmployeesIDOrdersID相关联选取数据:

8N&Qd6f$q0
SELECT Employees.Name, Orders.Product
FROM Employees, Orders
WHERE Employees.ID = Orders.ID

返回结果:51Testing软件测试网5[ r6|(gJv

1Pf,B.S_M&Q0Name51Testing软件测试网cvd)rP

51Testing软件测试网x+F:CZ5Od

Product

,q%q-@Y(Nk c0
51Testing软件测试网 D5]5h8l M:V#\'SY

Hansen, Ola51Testing软件测试网P _S`3A7GB+\

@o.X*`2oRl0Printer51Testing软件测试网/tL9Zyu]xi s

%JHfK6HFt0Svendson, Stephen51Testing软件测试网UI%^k6R*Q

GK2z_1] n$Qn(rg/W0Table

M8L r9F f.m]&q0
51Testing软件测试网6Z&U&GSS'O2U

Svendson, Stephen

0AaL%w xj P2U |!x0

!X5Oo@bS0Chair51Testing软件测试网bJ9Lx lUh*Xq

或者你也可以用JOIN关键字来完成上面的操作:51Testing软件测试网'?'i5fn&sT'O^

SELECT Employees.Name, Orders.Product
FROM Employees
INNER JOIN Orders
ON Employees.ID = Orders.ID

INNER JOIN的语法:51Testing软件测试网Zne,Ot1~

SELECT field1, field2, field3
FROM first_table
INNER JOIN second_table
ON first_table.keyfield = second_table.foreign_keyfield

解释:

nX:Nu#XIW8| k0

      INNER JOIN返回的结果集是两个表中所有相匹配的数据。

~VD+NdNx&f&L0

LEFT JOIN的语法:51Testing软件测试网Z4HD D+cY

SELECT field1, field2, field3
FROM first_table
LEFT JOIN second_table
ON first_table.keyfield = second_table.foreign_keyfield

”Employees”表去左外联结”Orders”表去找出相关数据:

(| M9XO*@1W0
SELECT Employees.Name, Orders.Product
FROM Employees
LEFT JOIN Orders
ON Employees.ID = Orders.ID

返回结果:

'Mg6L i h!h"d0

6O[oe%?6t4r)}],J0Name51Testing软件测试网 c3_;p YL B5Xy

:v+FXUiu0Product

\I.}5y U p0

"L]:?i|P9Sx0Hansen, Ola51Testing软件测试网2N*l PS1N

G1@YE2G;d0Printer

n0Z-X2U |b0
51Testing软件测试网|*{+e0V_ ]

Svendson, Tove

KOg7y)['|O0
51Testing软件测试网:b3J4w&me4y4UP E

 

%`)]l ^g%J0
51Testing软件测试网(Y rM9C:e

Svendson, Stephen

^ u;wl'W2`0

)y9Nbbm#XL H6p0Table51Testing软件测试网)@0dZp[

51Testing软件测试网$L$@p7zb)o~

Svendson, Stephen51Testing软件测试网 X.{"J*L%H%J

+q#n*m3d$k@k.t0Chair

HW+P!{:K Wmt0
51Testing软件测试网_&h"a{3g~ L

Pettersen, Kari51Testing软件测试网+q3|P ]*H

51Testing软件测试网v;E]*F ]x s6V

 51Testing软件测试网 ?1L/DGPrF1u5P]:|6E

解释:

9C_`2L2}@ |/Wc0

      LEFT JOIN返回first_table”中所有的行尽管在second_table中没有相匹配的数据。51Testing软件测试网$} {}+Zk^ P

RIGHT JOIN的语法:51Testing软件测试网Tu+m a?z/T

SELECT field1, field2, field3
FROM first_table
RIGHT JOIN second_table
ON first_table.keyfield = second_table.foreign_keyfield

”Employees”表去右外联结”Orders”表去找出相关数据:

I5gP@ T6B0
SELECT Employees.Name, Orders.Product
FROM Employees
RIGHT JOIN Orders
ON Employees.ID = Orders.ID

返回结果:

|7yBu0x5l;CpX;M,~%L0

?.?:mP(x*S|F0Name51Testing软件测试网 d~-z2OOm

Dgx+B%b*eK0Product51Testing软件测试网J,Ff8}$@8b

%jx'?A;yoD e#?$t+q0Hansen, Ola

+Rr3[F2{0
51Testing软件测试网'bH??1u

Printer51Testing软件测试网Bm(vjG"S W

USd0_c#q3r8o4W0Svendson, Stephen

DGYw.[[1` aI0

k!d}|R4j k0Table51Testing软件测试网 AcN/m@*m.z

51Testing软件测试网$DVT$z-|0x!c(d

Svendson, Stephen51Testing软件测试网W%A']7snx#i

51Testing软件测试网Ac3?5jzJ

Chair51Testing软件测试网 zF&M QXMRca

解释:51Testing软件测试网Fk_s q9` O

      RIGHT JOIN返回second_table中所有的行尽管在first_table”中没有相匹配的数据。51Testing软件测试网R-MQ!~r| A

Alias51Testing软件测试网 n/X'Ss]!_

用途:51Testing软件测试网\)n?%}#Y4zTuu

可用在表、结果集或者列上,为它们取一个逻辑名称51Testing软件测试网(i aN-G$p"|

语法:51Testing软件测试网#C3a"W B;R

给列取别名:

w%E8e&X*?.}n0
SELECT column AS column_alias FROM table

      给表取别名:51Testing软件测试网:f a2A'L[!A

SELECT column FROM table AS table_alias

例:51Testing软件测试网4i-htn+OZ x~K

“Persons”表中的原始数据:

4Dub%tj0| eg D*\0

/z+u5OL B!El8I.Y-e0LastName51Testing软件测试网/T,R FS$Y2Q4x]u

51Testing软件测试网;R7b:eM3J"h[&@

FirstName

]:tlM&P0

oD6H&rK:]H&?/?/T0Address51Testing软件测试网\,KuM-^j:Fp

51Testing软件测试网_aLoP*J8|E

City

J,nh:@;_BM \2f0

'? yH'QA'TQ0Hansen51Testing软件测试网 NL ?Bm0rI

51Testing软件测试网?~-imA/]

Ola51Testing软件测试网*dE,dLT qt yj(k

mK&Bucd0Timoteivn 1051Testing软件测试网m2z9a S"w;QdYb`:fp3S

m l(\KfM"t6U c0Sandnes51Testing软件测试网f#^%Ox4u!g"`

51Testing软件测试网 w R5IH!@%n1z;KK&U

Svendson

P"Af"O2nw0

;O0s;PP zZdl0Tove51Testing软件测试网$OF@fGr

V)]&i&}3~ro |;P0Borgvn 23

[6Pv"\t6}3|[J*mB0

m,dAmS(`8?X6BH0Sandnes51Testing软件测试网*G@W7mLv Q%\ ]o

51Testing软件测试网g'r],P!N/F1u

Pettersen51Testing软件测试网 y5a jrvU(u

51Testing软件测试网 P,C0j;f#g kc7ng

Kari51Testing软件测试网(Trw BC A

51Testing软件测试网m1P)F/h(T%u

Storgt 2051Testing软件测试网 tYl$DgK-mN,I*{/^JN&v

51Testing软件测试网.n2^9q7D o O}

Stavanger

`EBKE/l0

运行下面的SQL

AeA*W@x0
SELECT LastName AS Family, FirstName AS Name
FROM Persons

返回结果

$`/bT!R0O d/B\nB:M{0

+s7P8aKV | Ks+SH0Family51Testing软件测试网E2|Dl)t!PP

%Q(`2VV P-v'e%z0Name51Testing软件测试网1M G q z M ?7l&g

^{+u8B w)M(Y0Hansen51Testing软件测试网 X&`mX!x:S

/q@`1h n[(l'K/bh0Ola51Testing软件测试网"zOp Wq\;by+?

;Gmr,O7da*L0Svendson

F%} E0}^'e3HT$C0
51Testing软件测试网5lWct {$D ~j

Tove

ze7|~CT ]d1P0

/dHnq f0Pettersen

$`3A7i:WQ/jXdS0
51Testing软件测试网-W_Vfc%V

Kari51Testing软件测试网5iX(elt6h"N4F"OFL.`4H

运行下面的SQL51Testing软件测试网%b&O,p3b0u UAA

SELECT LastName, FirstName
FROM Persons AS Employees

返回结果

4D4E P4F [+`:M$s0

Employees中的数据有:51Testing软件测试网1JWt G1E4k)X;Ra

0h!s.B_4G"w-S9LY{8o0LastName

$o2C8O(fu'h0

#[Lg[2GUH;u0FirstName51Testing软件测试网0J$hiA_!z.Z

51Testing软件测试网lF8}G J\ CR

Hansen

B~9B-d)Tp Z!B0
51Testing软件测试网.d^KZ-g$Q6j+Q"]

Ola51Testing软件测试网VU;vN|~m0}5wDs-Q

*s*^4Oq8{x+N)[m \)}0Svendson

#A-C{\p j0

5ZW[)a"O'F` e0Tove51Testing软件测试网6WjH:]:iE2r,qp&O

51Testing软件测试网 y[[]w"Ji+AS

Pettersen

GM+~.{,Q|zH Zv0

[LS,w9j/[)Wo(h7I(Jlx0Kari

v%`QI*V|3a9| Nf@0

Insert Into51Testing软件测试网 z6joe%F*[ I B/^

用途:

+e })v N y*O$j0

      在表中插入新行51Testing软件测试网:Sk!o\ s(j"@ q

语法:51Testing软件测试网 hX9?R:z+PMi)T

      插入一行数据51Testing软件测试网8~ \ K1H\

INSERT INTO table_name
VALUES (value1, value2,....)

      插入一行数据在指定的字段上51Testing软件测试网n#v`+~gII1sZ]

INSERT INTO table_name (column1, column2,...)
VALUES (value1, value2,....)  

例:

E;t:cWL|0

“Persons”表中的原始数据:

$Qz0pnB#lST0

w%L-m hXG0LastName

:aDTx,_)e-pW0
51Testing软件测试网$i)B}*x{&`m

FirstName51Testing软件测试网lN&\ UZ:rt1\

51Testing软件测试网R kY8Ph z9C

Address

`+E4L-a0UM&i;Jm0
51Testing软件测试网/B8`%Q^8K9t;O

City

)p7r(`5E8U&C8\ iK@0|0

fSM9cZ"j#R0Pettersen

;|o)d8m3oi O3H0

G C wYiD9m8k0Kari51Testing软件测试网&Qh;O]@%u

51Testing软件测试网uI\m[e^o6WQ

Storgt 20

~#\1~u_@m(|!s Ox0

hS J&sV#M$WS0Stavanger51Testing软件测试网 u O g%[4[ u.GM2C0Q g

运行下面的SQL插入一行数据:51Testing软件测试网n D$_,I'myf^,P qO

INSERT INTO Persons 
VALUES ('Hetland', 'Camilla', 'Hagabakka 24', 'Sandnes')

插入后”Persons”表中的数据为

4a)s7EP4T0
51Testing软件测试网 e6pDoG]8oqI*U6Ed

LastName

yCE\(m(]8{ L6[ u0
51Testing软件测试网(z7r*wY0V

FirstName51Testing软件测试网-Y P T{G$\

Z1v)[.A$tZ Zc v/]0Address51Testing软件测试网%y+N!V#n'I*W

51Testing软件测试网GP0S2bh2_1j(f

City

)M0T.Ov3q)Rh|0q0
51Testing软件测试网3g;r*dr4bb O

Pettersen

(p{ GCxy0
51Testing软件测试网4bt G2q{

Kari

|` h+h6l0
51Testing软件测试网 H k SPug5z

Storgt 2051Testing软件测试网zNU+LvW

51Testing软件测试网8?$MP ke0P j4gj

Stavanger

:X{ N#@H4~p.F0

7T b1m?;G,i*U:r r Y9D0Hetland

-mAZX,hSl0

o5R gNU3P~0Camilla

{`g$@R}q,Da$\H0

Z?Y$_L0Hagabakka 2451Testing软件测试网_OTo0N-N

51Testing软件测试网c6{8WGaE|8[

Sandnes

bH3f#K~a1Qh0

运行下面的SQL插入一行数据在指定的字段上:51Testing软件测试网eyr2GY

INSERT INTO Persons (LastName, Address)
VALUES ('Rasmussen', 'Storgt 67')

插入后”Persons”表中的数据为51Testing软件测试网C'Va9Io {Fu

51Testing软件测试网^ C8Oqn

LastName

5ER!V9z4n3i-i0
51Testing软件测试网%Hs6r*o` w

FirstName

]+y#AuK8F;w$aSdg0

\ ?.`Y?t t0Address

7ERy/^2?-l0

p8`?*P0R:u!VZ z0City51Testing软件测试网Z X M.~9L2z

O)H+Za4v5J ed0Pettersen

V"M#H&PS`0
51Testing软件测试网-gb'^N&g H

Kari51Testing软件测试网OrMi6`'X ^[

51Testing软件测试网}q6UzaG

Storgt 20

9odUz7v U0
51Testing软件测试网 f7b zZ:D

Stavanger

5{p5FmP0

3E:|J(b`-g.L0Hetland51Testing软件测试网p P OJ4\)\1k

Aq]4I+~#rU3Q0Camilla51Testing软件测试网|H|!_K"sd5yw Y4]s

51Testing软件测试网/Ge0W5oq e z6m%j

Hagabakka 2451Testing软件测试网3['c2I'j;S-s_

51Testing软件测试网Z;B'mt2e8|F.m!ZY9l o

Sandnes51Testing软件测试网 Co~3Yo\z-A ?

51Testing软件测试网2R5|k4w"lh

Rasmussen

:V.[i6i4\e v0
51Testing软件测试网i,aF G_*nYwRG4`

 

@i`7oBB1t+A0
51Testing软件测试网+UD!]b&| b-\

Storgt 67

wD6R%e8W)@b'pa.Kg0

E d$[T j%q!z0 51Testing软件测试网X];B)Q3M;UF6l

Update51Testing软件测试网]{eA&rz9b`;|

用途:

k0G%_8Jn ph z+Rf0

      更新表中原有数据51Testing软件测试网2syIA7uwf

语法:

$^d6J B `.V0
UPDATE table_name SET column_name = new_value
WHERE column_name = some_value

例:

7j8D,?J#dn;c\x0

“Person”表中的原始数据:

IQ6?2N`0
51Testing软件测试网3`Ab8]'F6WR

LastName51Testing软件测试网)whKIh u2hWV h

(B8zjj;a;|U&Dr0FirstName

~R2Q7x5L7p2E Ze0
51Testing软件测试网?D.C S |t,hu8L+r

Address

+PvT%W!G|;A0

Z5L q Pmpmqvs$mb0City51Testing软件测试网6f w2G3V H'U j ?hl

R"\ | e%[a8L0Nilsen51Testing软件测试网@0F4^E/g/y3|+x"o

51Testing软件测试网k|SE*v(^q)y

Fred51Testing软件测试网6H{!n9]8_*j&B

P~ nu+i(Ue F7F y0Kirkegt 56

0]6R UU7a1w0
51Testing软件测试网yhRJH~!ox2p

Stavanger

(f$xU_&j(t!p0

)`:Z0EU$EU/er9s'e$uW8u0Rasmussen51Testing软件测试网(a&t6Rj ~

G-WX~O0 51Testing软件测试网|1m2o6e!d UC

JwH'M+jw0Storgt 6751Testing软件测试网{DZcl!C

:d F4X\Qt6d0 

u { j7\e"KWI0

运行下面的SQLPerson表中LastName字段为”Rasmussen”FirstName更新为”Nina”

*vi!r L#?a W0
UPDATE Person SET FirstName = 'Nina'
WHERE LastName = 'Rasmussen'

更新后”Person”表中的数据为51Testing软件测试网T o\}0EE\ I

$C^ D/T%|0LastName51Testing软件测试网)lf'|7j5u

51Testing软件测试网.X5mF,\[

FirstName51Testing软件测试网;F(Y hrI/H

4Gm3\!g N;M+GW0Address51Testing软件测试网`8Lf3A LC

51Testing软件测试网_MM3s&c"^XD

City

t+{/SC0hR]*H+o0

~ L|4UUc8ln*u2T0Nilsen

:T cW5T]D0
51Testing软件测试网-r1A-n1Bi-?_^#F5a

Fred

6px.B'UP+SZ)y0
51Testing软件测试网)`Tc t oQ$a

Kirkegt 5651Testing软件测试网+sp2a;AO#j7H

4`.@)Z2s+nww0Stavanger

L-jP'vb@_;Dy0

R0aj)J-Z7q0Rasmussen51Testing软件测试网d}Q U-cn-s'z

51Testing软件测试网r9K?B'] xx4sa$v

Nina

KV*wSH ]0

A1E&A)F/@Z;Y hO0Storgt 6751Testing软件测试网/Ag)`|#AB

51Testing软件测试网R]v0s0u

 

Lhs:kd$cR7e+X0

同样的,用UPDATE语句也可以同时更新多个字段:

0@5Y;B,^ YE%C)}9e D0
UPDATE Person
SET Address = 'Stien 12', City = 'Stavanger'
WHERE LastName = 'Rasmussen'

更新后”Person”表中的数据为51Testing软件测试网9n9k p2N6nEhOO

!X}8|j4T5E2O6d wc0LastName51Testing软件测试网dvOU-J6er}

51Testing软件测试网p,iU3Jy!S)q%w

FirstName51Testing软件测试网X oKb!coS

~*JS7SFJ`"u0Address51Testing软件测试网XgO(FE$}1?x}

(u/a(T/tX l6Hv@0City51Testing软件测试网^J7I-dF{

51Testing软件测试网4T ut"q"B [v5g

Nilsen

1|;cKig1Gu0

e O*[5~/P0Fred

a:Z["gV%b6? D[`c0
51Testing软件测试网 Nlg}Jx]

Kirkegt 5651Testing软件测试网(mB"Y"f"OU^

'YS&txA\!I_0Stavanger

.lvYLSn+Jz0
51Testing软件测试网;w(KMP$q6\{W$j

Rasmussen51Testing软件测试网,cp^ q#P2j9G

4{THz+q.L;_2L0Nina

2lX}V Tjq0
51Testing软件测试网z L5J]dW4d"{aH

Stien 12

LNj tH|7H0
51Testing软件测试网$]x*d1PCcx^g/M6x

Stavanger

d*};B6d%@fs#g1V^"m0

Delete51Testing软件测试网l~?I:?J:[1Uq

用途:51Testing软件测试网%s~I'k!ka![+Lz

      删除表中的数据

?9ataat0

语法:51Testing软件测试网.SZw2A7AAbn%x

DELETE FROM table_name WHERE column_name = some_value

例:

{ @cE#p:E/k0

“Person”表中的原始数据:

'f ks$pl6^u0
51Testing软件测试网Y6YI2e;j@O

LastName51Testing软件测试网*UWWk W+Z$u7z P

51Testing软件测试网v[Tx \d u qW

FirstName51Testing软件测试网`A'I;FbQ&{a N7d

l)k#ug#X0Address

'd*SQEfQW0
51Testing软件测试网G^D r3JaxP|

City

j1Y'y.RyX5vxh2g8I0

6w4C0A~7N d0Nilsen

sntCOF I Y0
51Testing软件测试网'[4`Y{N]#r

Fred51Testing软件测试网} w+fAiZD4EDBZy7N

51Testing软件测试网;r"n2d Z X

Kirkegt 56

*w3]nK0Rv B0
51Testing软件测试网Q'V'@%u?.d"]T

Stavanger51Testing软件测试网9?BR;KG\

)o~oJMH \0Rasmussen

uo df7Vh^y-bR0
51Testing软件测试网2]P `N h7s"L5u8J

Nina

l+S:X A.y g)G-DbP0
51Testing软件测试网;T B;i zPy]*_m

Stien 12

[$z/L,d1v5\7O~0
51Testing软件测试网N m9@2E4^N3R?G7s

Stavanger

'gQ-I_b}6d0

删除Person表中LastName”Rasmussen”的数据:51Testing软件测试网I*l"`O XYh0\

DELETE FROM Person WHERE LastName = 'Rasmussen'

执行删除语句后”Person”表中的数据为51Testing软件测试网 q1j0l+V9WpR aQw

51Testing软件测试网9B'Wu? B6YS~

LastName

5Z8x4?NiFND0
51Testing软件测试网mY'J["yv4s

FirstName51Testing软件测试网8@ j2Rwk

51Testing软件测试网C3]$R*B T3mQ

Address

|2?@ }"uh0

M:? H:Zj0City

4M:i#Mi2e"a0
51Testing软件测试网*zJr5YIV

Nilsen51Testing软件测试网v4K4|;K S`T8t0C

uX"lq M B/l0Fred51Testing软件测试网?3}0\,q D @kVGQD

9K6P3G\*L$k)Z0Kirkegt 56

\4J.JW%Of0
51Testing软件测试网$~4W6Rew(m

Stavanger51Testing软件测试网J2A1Bk:?@+W

Create Table

C*ti0L9_CSfI!X0

用途:

'@\ x!Kri V'@*Hs0

      建立新的资料表。

,T Bl&q p'c0b9If!CcJ0

语法:

2lbe6V![*T0
CREATE TABLE table_name
(
column_name1 data_type,
column_name2 data_type,
.......
)

例:

#Dm V{ L]'w#k0

创建一张叫“Person”的表,该表有4个字段"LastName", "FirstName", "Address", "Age"51Testing软件测试网8qXUC0@

CREATE TABLE Person 
(
LastName varchar,
FirstName varchar,
Address varchar,
Age int
)

如果想指定字段的最大存储长度,你可以这样:

%J{(| SuX)F?0
CREATE TABLE Person 
(
LastName varchar(30),
FirstName varchar(30),
Address varchar(120),
Age int(3) 
)

下表中列出了在SQL的一些数据类型:

Xw'm+lI^q6bch0

5J!F[1L_.y.Z+e0Data Type

)o&x&vK!^UL([m*|d0
51Testing软件测试网%Q:I\o.q|Qkr

Descrīption51Testing软件测试网/m8v2?^E0|t

51Testing软件测试网{G V%T ll yk

integer(size)51Testing软件测试网)u |p [f|:pq
int(size)
"|eJtj9a0li0smallint(size)51Testing软件测试网JMP/W4Q
tinyint(size)

M J#E/S*{g0
51Testing软件测试网.Ov!nQ|7v_:`

Hold integers only. The maximum number of digits are specified in parenthesis.51Testing软件测试网*csC[+A/d

51Testing软件测试网5`;ewgfo g

decimal(size,d)
q^]f9y&`gB'R0numeric(size,d)
51Testing软件测试网N"g$AE1T/rtu.Y

51Testing软件测试网+r8bI;yewW

Hold numbers with fractions. The maximum number of digits are specified in "size". The maximum number of digits to the right of the decimal is specified in "d".

s(N)f7x1z0

4|_ c8}oQ0char(size)51Testing软件测试网8T!o"J xX E1_~:f#@-N

7t3v^I$Z AP:uT;N0Holds a fixed length string (can contain letters, numbers, and special characters). The fixed size is specified in parenthesis.51Testing软件测试网 b8k;O)V,m$l9F

51Testing软件测试网S?t3?bP7R$F!C

varchar(size)

j/B:Az,h3h-OMI3`Lp0

Ls~)X#E$m m H0Holds a variable length string (can contain letters, numbers, and special characters). The maximum size is specified in parenthesis.

0T*Yce8c0
51Testing软件测试网R oYBA1V8PZ

date(yyyymmdd)51Testing软件测试网DARzW5[*A,Mb6|

{:P ? s"b{2Mi){0Holds a date

aT3^ Mc!D0

Alter Table51Testing软件测试网 dC!p.p!F

用途:

4? @*D#N3k1d9uBk0

      在已经存在的表中增加后者移除字段51Testing软件测试网7_(Z J"W4B raRi

语法:51Testing软件测试网#M5c Is([b

ALTER TABLE table_name
ADD column_name datatype
ALTER TABLE table_name
DROP COLUMN column_name

注意:某些数据库管理系统不允许移除表中的字段51Testing软件测试网 B]/}}`7k@"MG(P'tm4@

例:51Testing软件测试网6KdW&c oQ_

“Person”表中的原始数据:51Testing软件测试网^[.?:m t:FNZ

J*r\n7f9a!q YA1_4u0LastName

i#i+\,y%y T _&OH$T0

]7f o7P5G0FirstName51Testing软件测试网D9l k IX

51Testing软件测试网djM5Hn

Address51Testing软件测试网 QPwE1Ut

WV!Z5LH0M(m8j|0Pettersen

F~?*|dK#L+]u0

~4wCX_'I#tI0Kari

*i+IU0JE.uu0

Ad5r0lp3yj"K v,g0Storgt 20

\*g2F5P ll @0

Person表中增加一个名为City的字段:

Gp:k-wh |/c0
ALTER TABLE Person ADD City varchar(30)

增加后表中数据如下:51Testing软件测试网KC[_V9Q)~t

51Testing软件测试网]3kgt'Q

LastName51Testing软件测试网|:]/?7D+}

51Testing软件测试网]hmZ8ddE

FirstName

:i,x1k#F2O$Ql4wv#g3aq0
51Testing软件测试网 si%IB6Aq s

Address

:oMpWg`~0
51Testing软件测试网)r J km |*U}

City51Testing软件测试网g8N2x$Xo

51Testing软件测试网7s7N+fb4b!R

Pettersen51Testing软件测试网 f+kUmxm

/Lwt)A1j ]rw0Kari

,Ob%b5xT'R0
51Testing软件测试网9hB!WL5Ds!^i

Storgt 2051Testing软件测试网 Q(}@,Ie-t)GJd@

51Testing软件测试网$@6Q$S3T)?(\2c i+?

 51Testing软件测试网w5i*B1x)@"BO1{"c

移除Person表中原有的Address字段

&IKF0x:{&S;M0
ALTER TABLE Person DROP COLUMN Address

移除后表中数据如下:51Testing软件测试网xbkn\z$hE!W

h d` U [i0LastName51Testing软件测试网q(mJ@/F0Z F

51Testing软件测试网3F7mMk O WT

FirstName51Testing软件测试网2[H8U'y,_ T;e1d;B&Tw

!KU%@ St0City51Testing软件测试网:K:K2d9a9_ h$A

od[TH e0Pettersen

v)B+cT _? y b0
51Testing软件测试网\ Q;^W'N@

Kari51Testing软件测试网&}3pE8f"Nb,z`y

51Testing软件测试网v:^^ [c/?*r

 51Testing软件测试网g6Q$i%pE3o

Drop Table

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用途:51Testing软件测试网*B)a#[0YE]k

      在数据库中移除一个数据表定义及该数据表中的所有资料、索引、触发程序、条件约束及权限指定。

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语法:

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DROP TABLE table_name

Create Database

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用途:

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      建立新的数据库.

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语法:51Testing软件测试网y K}'I!y4COj!x

CREATE DATABASE database_name

Drop Database

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用途:

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      移除原有的数据库51Testing软件测试网xH'Q%E1VCy

语法:

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DROP DATABASE database_name

聚集函数51Testing软件测试网 |0R6d7O&W Y-UB F6}r~

count

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用途:

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      传回选取的结果集中行的数目。

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语法:51Testing软件测试网Ir$b\A(W

SELECT COUNT(column_name) FROM table_name

例:

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“Persons”表中原始数据如下:

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Name51Testing软件测试网pom@u+K6B'NR

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选取记录总数:

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SELECT COUNT(Name) FROM Persons

执行结果:

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sum51Testing软件测试网'k:G0Ll{#J9n

用途:51Testing软件测试网2D|@dP-l ci&Nb

      以表达式传回所有值的总和,或仅DISTINCT值。SUM仅可用于数值资料行。已忽略Null值。

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语法:

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SELECT SUM(column_name) FROM table_name

例:

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“Persons”表中原始数据如下:

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Name51Testing软件测试网7g lw#EY:L3`%r*W$h

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Age

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Hansen, Ola

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34

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Svendson, Tove

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Pettersen, Kari

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选取”Persons”表中所有人的年龄总和:

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SELECT SUM(Age) FROM Persons

执行结果:

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选取”Persons”表中年龄超过20岁的人的年龄总和:51Testing软件测试网#ao_t_4FJ

SELECT SUM(Age) FROM Persons WHERE Age>20

执行结果:

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avg51Testing软件测试网!?.T+q^I)tR?7^9c

用途:

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      传回选取的结果集中值的平均值。已忽略Null 值。51Testing软件测试网m2BE!m6pBC

语法:

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SELECT AVG(column_name) FROM table_name

例:

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“Persons”表中原始数据如下:51Testing软件测试网f9JNO+V&T

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Name

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M w3TuCM0|@0Age

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Hansen, Ola51Testing软件测试网e%hn8azinrb

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Svendson, Tove

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Pettersen, Kari

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选取”Persons”表中所有人的平均年龄:

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SELECT AVG(Age) FROM Persons

执行结果:51Testing软件测试网%p W{t3G`H,v

TAG: Oracle

 

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