Question

我正在尝试将gradu_term表中相应的gradu_date值复制到user_education_mba_school表中具有匹配gradu_term_id的行中。这是我的非工作查询

TABLE DEFS
**user_education_mba_school
  school_id
  graduation_date
  graduation_term_id

**graduation_term
  graduation_term_id
  graduation_year_id
  graduation_date

**graduation_class
  graduation_class_id
  graduation_year_id  

**user
  user_id
  graduation_class_id

- 多连接无法正常工作......

UPDATE  u
SET     graduation_class_id = gc.graduation_class_id
FROM    [user] u
JOIN    user_education_mba_school mba
ON      mba.user_id = u.user_id
JOIN    graduation_term gt
ON      mba.graduation_term_id = gt.graduation_term_id
JOIN    graduation_class gc
ON      gt.graduation_year_id = gc.graduation_year_id

Answer 1

有几个数据库支持update ... from语法，这很清楚：

UPDATE  mba
SET     graduation_date = gt.graduation_date
FROM    user_education_mba_school mba
JOIN    graduation_term gt
ON      gt.graduation_term_id = mba.graduation_term_id

如果您的数据库没有，请澄清您正在使用的数据库。

Answer 2

这不起作用，因为您正在设置子查询的整个结果集

UPDATE user_education_mba_school SET graduation_date = (
  SELECT gt.graduation_date
  FROM user_education_mba_school mba, graduation_term gt
  WHERE gt.graduation_term_id = mba.graduation_term_id
)

这应该有效（未经测试）

UPDATE user_education_mba_school mba SET graduation_date = (
  SELECT gt.graduation_date
  FROM graduation_term gt
  WHERE gt.graduation_term_id = mba.graduation_term_id
)

Answer 3

UPDATE  mba
SET     graduation_date = gt.graduation_date, mba_graduation_year_id = gt.graduation_year_id
FROM    user_education_mba_school mba
JOIN    [sueldovista].dbo.graduation_term gt
ON      gt.graduation_term_id = mba.graduation_term_id


UPDATE  u
SET     graduation_class_id = gc.graduation_class_id
FROM    [user] u
JOIN    user_education_mba_school mba
ON      mba.user_id = u.user_id
JOIN    [sueldovista].dbo.graduation_term gt
ON      mba.graduation_term_id = gt.graduation_term_id
JOIN    [sueldovista].dbo.graduation_class gc
ON      gt.graduation_year_id = gc.graduation_year_id
WHERE   gc.site_instance_id = 1

Answer 4

ORACLE：

更新生产a SET（姓名，计数）=（ SELECT名称，计数从分段b WHERE a.ID = b.ID）;

sql使用subselect更新多行

4 个答案: