表A:
ID,Name
表B:
ID,Name
现查询表A,想知道表B中有无ID相同的记录,如有则显示有几条,下面语句在mysql中无法执行
select
ID,
Name,
(select cont(*) from 表B where ID=表A.ID)表B_IDfrom 表A
ID,Name
表B:
ID,Name
现查询表A,想知道表B中有无ID相同的记录,如有则显示有几条,下面语句在mysql中无法执行
select
ID,
Name,
(select cont(*) from 表B where ID=表A.ID)表B_IDfrom 表A
(select count(*) from 表B where `ID`=表A.`ID`) as `表B_ID` from 表A
syntax to use near'(select count(*) from 表B where ID=表A.ID)'建议准确贴出你的语句,这样减少误导。
(select cont(*) from 表B where ID=表A.ID)表B_ID
syntax to use near'(select count(*) from 表B where ID=表A.ID)'
上面一句cont(*)写错了,应该是count(*)。
谢谢!
就是想实现查询表A时看表B中有无ID相同的纪录。
select 表A.ID,表A.Name,count(表B.ID)
from 表A left join 表B on 表A.ID=表B.ID
group by 表A.ID,表A.Name
表A:
ID,Name,EmployeeID
表C:
EmployeeID,EmployeeName
现在想同时列出EmployeeName,达到如下效果:
ID,Name,count,EmployeeID,EmployeeName
from 表A inner join 表C on 表A.EmployeeID=表C.EmployeeID
left join 表B on 表A.ID=表B.ID
group by 表A.ID,表A.Name,表C.EmployeeID,表C.EmployeeName
select 表A.ID,表A.Name,表C.EmployeeID,表C.EmployeeName,count(表B.ID)
from 表A inner join 表C on 表A.EmployeeID=表C.EmployeeID
left join 表B on 表A.ID=表B.ID
group by 表A.ID,表A.Name,表C.EmployeeID,表C.EmployeeName