postgresql 在使用 LEFT OUTER JOIN 时添加条件
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Add condition while using LEFT OUTER JOIN
提问by Deepak Kumar
I have two table i want to add one condition while using LEFT OUTER JOIN
我有两张表，我想在使用 LEFT OUTER JOIN 时添加一个条件
select tt.description,tt.visible,vct.currvalue
from tblemployee tt
left outer join viwcurrentemployee vct on vct.transitiontype = tt.cid
and vct.employee = 63
and tt.visible = 1
order by tt.cid
i want only those record which is have visible = 1 that is true but query ignore the condition and one thing i must have to use left outer join coz i want record from left table even record not present in right table how to check the condition that i will get only those record from left table in which visible is 1
我只想要那些可见的记录 = 1 是真的，但查询忽略条件，还有一件事我必须使用左外连接因为我想要从左表中记录，即使右表中不存在记录如何检查条件我将只从左表中获取可见为 1 的那些记录
回答by Mikael Eriksson
Try this
试试这个
select tt.description,
tt.visible,
vct.currvalue
from tblemployee tt
left outer join viwcurrentemployee vct
on vct.transitiontype = tt.cid and
vct.employee = 63
where tt.visible = 1
order by tt.cid
I moved tt.visible = 1to the where clause instead. vct.employee = 63need to stay in the join because otherwise you would not have an outer join.
我tt.visible = 1改为使用 where 子句。vct.employee = 63需要留在连接中，否则您将没有外部连接。
回答by StevieG
select tt.description,tt.visible,vct.currvalue
from tblemployee tt
left outer join viwcurrentemployee vct on vct.transitiontype = tt.cid
and vct.employee = 63
where tt.visible = 1
order by tt.cid
