PB组合查询

查询按钮的代码为：
int flag=0
string s_name,s_phone,sqlstr
s_name=trim(sle_name.text)
s_phone=trim(sle_phone.text)
sqlstr='select column1,column2 from table where '

if cbx_name.checked=true and cbx_phone.checked=true then
sqlstr=sqlstr+'column_name="'+s_name+'"'+' and column_phone="'+s_phone+'"'
else
if cbx_name.checked=true then
if flag=0 then
sqlstr=sqlstr+'column_name="'+s_name+'"'
flag=1
else
sqlstr=sqlstr+' and column_name="'+s_name+'"'
end if
if cbx_phone.checked=true then
if flag=0 then
sqlstr=sqlstr+'column_phone="'+s_phone+'"'
flag=1
else
sqlstr=sqlstr+' and column_phone="'+s_phone+'"'
end if
end if
dw_1.setsqlselect(sqlstr)
dw_1.retrieve()