将头分配给查询mysql
我有一个问题将头分配给查询mysql,mysql,Mysql,我有一个问题 select abc from table1 union select def from table2 我希望将结果作为不同的标题组合在一起 我正在努力 Select * as diff (select abc from table1 union select def from table2) 查询应该是什么,以便将结果聚集在第三列标题diff中 谢谢只需在第一选择中使用标题别名: select abc as diff from table1 union select def
select abc from table1 union select def from table2
我希望将结果作为不同的标题组合在一起
我正在努力
Select * as diff (select abc from table1 union select def from table2)
查询应该是什么,以便将结果聚集在第三列标题diff中
谢谢只需在第一选择中使用标题别名:
select abc as diff from table1 union
select def from table2
如果我理解正确,您希望在外部查询中有一个自定义列名。
您可以通过特别引用要重命名的列来完成此操作。
以下是一个例子:
create table t (c varchar(10));
create table t2 (c2 varchar(10));
insert into t values ('abc');
insert into t2 values ('def');
select s.c as t
from (
select c
from t
union
select c2
from t2
) s;
结果:
t
---
abc
def
有关参考资料,请参阅: