mysql - View的SELECT在FROM子句MySQL语句中包含子查询

Question

我有一个关于在 MySQL Workbench 中创建 View 的问题。保存时出现错误:“ View 的 SELECT 在 FROM 子句中包含一个子查询”。

这是我声明的副本:

CREATE VIEW viewMorningReport AS 
select z.AllocationDate, z.LocationName, z.StationName, a.00000100, b.01000200, c.02000300  from
(SELECT DISTINCT AllocationDate, LocationName, StationName FROM satsschema.employeeslot
where LocationName = 'T2 PML'
and StationName is not null) z
left outer join 
(SELECT AllocationDate, LocationName, StationName, EmpName AS '00000100' FROM     satsschema.employeeslot
WHERE Assigned = true
and (EmpTime = '00:00:00' && EmpTime < '01:00:00')) a
on z.LocationName = a.LocationName and z.StationName = a.StationName
left outer join
(SELECT  AllocationDate, LocationName, StationName, EmpName AS '01000200' FROM    satsschema.employeeslot
WHERE Assigned = true
and (EmpTime = '01:00:00' && EmpTime < '02:00:00')) b
on a.LocationName = b.LocationName and a.StationName = b.StationName
left outer join
(SELECT  AllocationDate, LocationName, StationName, EmpName AS '02000300' FROM satsschema.employeeslot
WHERE Assigned = true
and (EmpTime = '02:00:00' && EmpTime < '03:00:00')) c
on b.LocationName = c.LocationName and b.StationName = c.StationName

知道哪里出了问题吗？

Answer 1

作为the official documentation says

E.4. Restrictions on Views

(..)

Subqueries cannot be used in the FROM clause of a view.

一个选项可能是为每个子查询创建一个 View 。另一个是修改您的 View ，以避免 from 子句中的 subquery