从 tableB 插入 tableA where condition set case

Question

1st question:

我正在尝试从我有条件的表 B 插入表 A 字段并为列 A 设置大小写，但它不起作用。是否可以在没有更新的情况下进行？

insert into tableA
select date, columnA 
from tableB
where tableB.date between '2015-10-01' and '2015-10-31'
set columnA = case
              when columnA like ('%aaa%') then 'aaa'
              when columnA like ('%bbb%') then 'bbb'
              when columnA like ('%ccc%') then 'ccc'
              when columnA like ('%ddd%') then 'ddd'
              when columnA like ('%eee%') then 'eee'
              else columnA 
              end
;

wchiquito 回复并且有效。

2nd question:

此外，如果我还想按日期和A列分组，我想看看第一个问题的解决方案。

我能做到:

insert into tableA
select date, case
              when columnA like ('%aaa%') then 'aaa'
              when columnA like ('%bbb%') then 'bbb'
              when columnA like ('%ccc%') then 'ccc'
              when columnA like ('%ddd%') then 'ddd'
              when columnA like ('%eee%') then 'eee'
              else columnA 
              end
from tableB
where tableB.date between '2015-10-01' and '2015-10-31'
group by date, case
              when columnA like ('%aaa%') then 'aaa'
              when columnA like ('%bbb%') then 'bbb'
              when columnA like ('%ccc%') then 'ccc'
              when columnA like ('%ddd%') then 'ddd'
              when columnA like ('%eee%') then 'eee'
              else columnA 
              end
;

不过我也想看看有没有别的办法。避免重复编写案例的更好方法。

Answer 1

记住 column 是保留字，参见 9.3 Keywords and Reserved Words。

见，12.4 Control Flow Functions - CASE。

INSERT INTO `tableA`
SELECT `date`, CASE
                WHEN `column` LIKE '%aaa%' THEN 'aaa'
                WHEN `column` LIKE '%bbb%' THEN 'bbb'
                WHEN `column` LIKE '%ccc%' THEN 'ccc'
                WHEN `column` LIKE '%ddd%' THEN 'ddd'
                WHEN `column` LIKE '%eee%' THEN 'eee'
                ELSE `column`
              END
FROM `tableB`
WHERE `tableB`.`date` BETWEEN '2015-01-01' AND '2015-01-04';

SQL Fiddle demo

从 tableB 插入 tableA where condition set case

Insert into tableA from tableB where condition set case

mysql

insert

set