我想把a列,b列,c列 合并成一列怎么处理?请前辈指点
我想把a列,b列,c列 合并成一列怎么处理?请前辈指点

[解决办法]
select a from tablename
union all
select b as a from tablename
union all
select c as a from tablename
[解决办法]
用UNION (ALL)

SELECT A FROM ...
UNION ALL SELECT B FROM...
UNION ALL SELECT C FROM...
[解决办法]
select a from tablename
union all
select b as a from tablename
union all
select c as a from tablename