我有下表:
ID, initials, surname, company, active
1, p, abc, com1, 0
2, p, abc, com1, 0
3, c, acb, com1, 0
4, c, def, com1, 0
5, c, def, com1, 0
现在我想将“姓名缩写,姓氏,公司”的重复组合更新为状态1,从而产生以下结果:
ID, initials, surname, company, active
1, p, abc, com1, 0
2, p, abc, com1, 1
3, c, acb, com1, 0
4, c, def, com1, 0
5, c, def, com1, 1
选择正在运行:
SELECT DISTINCT initials, surname, company
FROM table
我试过了,但是没有用:
UPDATE table
SET active = 1
WHERE EXISTS( SELECT DISTINCT initials, surname, company)
答案 0 :(得分:7)
UPDATE table AS t
JOIN table AS tt
ON t.initials = tt.initials
AND t.surname = tt.surname
AND t.company = tt.company
AND t.id > tt.id
SET t.active = 1;
也就是说,对于每一行,如果存在另一个id较低的行,并且具有相同的姓名,姓氏和公司,则更新它。
这是sqlfiddle。