SQL语句 问题
select * from emp where emp_name like '%% ' and EMP_SEX like '%% ' and DEPT_ID like '%% ' and DUTY_ID like '%% ' and OPSITION_ID like '%% ' and EMP_SPEC like '%% ' and EMP_IDENTITY_CARD like '%% '
愿句为： string sql = "select * from emp where emp_name like '% " + name + "% ' and EMP_SEX like '% " + sex + "% ' and DEPT_ID like '% " + dept + "% ' and DUTY_ID like '% " + duty + "% ' and OPSITION_ID like '% " + option + "% ' and EMP_SPEC like '% " + sep + "% ' and EMP_IDENTITY_CARD like '% " + cardid + "% ' ";
请问我这语句有何问题？？？？？？？？？？？
[解决办法]
LZ说: 这么写主要是我有7个参数，但是结合起来的判断条件要是一个一个来就有2的7次幂个条件。
那么下面这样可以么?
select * from emp where (参数1= ' ' or emp_name like '%参数1% ') and (参数2= ' ' or EMP_SEX like '%参数2% ') and (参数3= ' ' or DEPT_ID like '%参数3% ') and (参数4= ' ' or DUTY_ID like '%参数4% ') and (参数5= ' ' or OPSITION_ID like '%参数5% ') and (参数6= ' ' or EMP_SPEC like '%参数6% ') and (参数7= ' ' or EMP_IDENTITY_CARD like '%参数7% ' )
[解决办法]
不用那么多If判断，这样写就可以：
select *
from emp
where (emp_name like '% ' + @emp_name + '% ' or @emp_name is null)
and (EMP_SEX like '% ' + @EMP_SEX + '% ' or @EMP_SEX is null)
and (DEPT_ID like '% ' + @DEPT_ID + '% ' or @DEPT_ID is null)
and (DUTY_ID like '% ' + @DUTY_ID + '% ' or @DUTY_ID is null)
and (OPSITION_ID like '% ' + @OPSITION_ID + '% ' or @OPSITION_ID is null)
and (EMP_SPEC like '% ' + @EMP_SPEC + '% ' or @EMP_SPEC is null)
and (emp_name like '% ' + @EMP_IDENTITY_CARD + '% ' or @EMP_IDENTITY_CARD is null)
对于为空的，传入System.DBNull
