SQL更新语句与where子句中的子查询相同的表

我目前是一名学生，我正试图解决SQL的一个小问题。我想根据来自同一个表的过滤结果在表上执行更新语句。 Here is the table I have:SQL更新语句与where子句中的子查询相同的表

这是查询我到现在：

UPDATE ComplexityLessons 
SET ACADEMYRATIO = '0,896' 
WHERE (
    SELECT c.START, c.DATE, c.ACTIVITY, c.ACADEMY 
from ComplexityLessons c 
join (
    SELECT b.ACTIVITY, b.START, b.DATE 
    FROM ComplexityLessons b 
) as b 
on c.ACTIVITY = b.ACTIVITY and c.DATE = b.DATE and c.START = b.START 
having COUNT(DISTINCT ACADEMY) = 2)

所以，总结我想更新列“ActivityRatio”仅在2所院校在同一时间进行同样的活动。当我仅使用子查询时，我得到了同时执行相同活动的院校，但我无法弄清楚更新声明。预先感谢您的帮助！

来源

2017-03-16 Stanislav Diulgiarski

您使用MySQL，MS SQL Server或Oracle吗？不要标记不涉及的产品！ – jarlh

@jarlh：我使用phpmyadmin，所以MySQL。 –

UPDATE ComplexityLessons SET ACADEMYRATIO = '0,896' 
WHERE (SELECT c.START, c.DATE, c.ACTIVITY, c.ACADEMY 
     from ComplexityLessons c 
join (SELECT b.ACTIVITY, b.START, b.DATE 
     FROM ComplexityLessons b) as b 
on c.ACTIVITY = b.ACTIVITY and c.DATE = b.DATE and c.START = b.START 
having COUNT(DISTINCT ACADEMY) = 2)

在哪里应该有条件和子查询应该返回ID。例如

UPDATE ComplexityLessons SET ACADEMYRATIO = '0,896' 
WHERE <id> in (SELECT <id> from ComplexityLessons c 
join (SELECT b.ACTIVITY, b.START, b.DATE 
     FROM ComplexityLessons b) as b 
on c.ACTIVITY = b.ACTIVITY and c.DATE = b.DATE and c.START = b.START 
having COUNT(DISTINCT ACADEMY) = 2)

的应该是表之间的foriegn键。

来源

2017-03-16 14:38:29

我试过了，但它仍然给我错误“操作数应该只包含一列” –

请提供您使用的最新查询。 –

UPDATE ComplexityLessons SET ACADEMYRATIO ='0,896'WHERE ACTIVITY IN（SELECT c.START，c.DATE，c.ACTIVITY，c.ACADEMY from ComplexityLessons c join（SELECT b.ACTIVITY，b.START，b.DATE FROM ComplexityLessons b）作为b对c.ACTIVITY = b.ACTIVITY和c.DATE = b.DATE和c.START = b.START有COUNT（DISTINCT ACADEMY）= 2）@Sambi Reddy –

SQL更新语句与where子句中的子查询相同的表

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