select distinct id from names where tid = 'AREACODE' And dsc

来源：学生作业帮编辑：作业帮分类：综合作业时间：2024/05/09 11:48:26

select distinct id from names where tid = 'AREACODE' And dsc like '%' || v_areacode
其中dsc like '%' || v_areacode

||是ORACLE数据库字符串拼接的符号,相当于SQLSERVER中的+
你这个例子,就是把前面的字符串'%'和后边的变量实现字符串拼接
再问：我现在的理解是若变量v_areacode=400, dsc like '%' || v_areacode 就相当于dsc like '%400',这样理解对吗, 还是有点想不明白的,还是说应该是dsc like %400,like后能接不带''的字符吗
再答：对，dsc like '%' || v_areacode，v_areacode = '400'，就是查询以400结尾的字符串 dsc like %400 是不对的，应该是dsc like '%400'，这才是正确的语法。这里面，v_areacode变量，要求必须是字符型的，因为||是字符串拼接的符号，左右两边必须是字符串才能完成拼接。

select distinct id from names where tid = 'AREACODE' And dsc select distinct A.* from A,B where A.id = B.g_id and A.fwzid sql如何取交集有这样两条sql语句select distinct id from a where id='123'se select * from order where clientNo in (select distinct(clien SELECT COUNT(*) FROM Users WHERE Id={0} AND LoginPwd = '{1}' select id,name from student where id in ( select id from sco select ** from A where A.id in (select id from B where ****) $id="select id from account where name='".$_SESSION['login'] $query = mysql_query( select * from 表名 where id='$_GET[id]' sql 中 select * from A left join B on A.id=B.id where A.id=?如 select count(distinct b) from X_info where c=1;能放到一个CASE内么不 sql="select * from "&data&" where id="&myid&"" 在数据库中没有data 这