本文介绍了将2个SQL SELECT结果集合并为一个的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!
问题描述
我有2条select语句,返回的数据如下:
I've got 2 select statements, returning data like this:
Select 1 col_a col_b Select 2 col_a col_c如果我参加工会,我会得到类似的东西
If I do union, I get something like
col_a col_b行合并.我需要的是这样的:
And rows joined. What i need is getting it like this:
col_a col_b col_c已加入col_a
推荐答案使用JOIN连接子查询,并使用ON表示每个子查询中的行必须匹配的位置:
Use JOIN to join the subqueries and use ON to say where the rows from each subquery must match:
SELECT T1.col_a, T1.col_b, T2.col_c FROM (SELECT col_a, col_b, ...etc...) AS T1 JOIN (SELECT col_a, col_c, ...etc...) AS T2 ON T1.col_a = T2.col_a如果T1中有一些col_a值,而T2中没有,则可以改用LEFT OUTER JOIN.
If there are some values of col_a that are in T1 but not in T2, you can use a LEFT OUTER JOIN instead.
更多推荐
将2个SQL SELECT结果集合并为一个
发布评论