Question

我的问题与附件中的问题非常相似，只是我需要在查询中有一个与table1相关的where子句。我的table2（t2）只有一列（名称）而没有日期/时间列，而table1（t1）有name，sales和week。我希望为Sean返回零，因为他在截至01/01/2017的那一周没有任何销售。

Create a third table from two tables

select * from table2:

Names

Maggie
Colleen
Laura
Sean

select * from table1:

Names               Sales                Week
Maggie              1800                 01/01/2017
Colleen             2000                 01/01/2017  
Laura               4000                 01/01/2017
Sean                1500                 12/18/2016   

select t2.Name, coalesce(t1."Employee Sales",0) "Employee Sales"
from emphis t2 left outer join
(select Name, sum(Sales) "Employee Sales"
from empdata
group by Name) t1
on t1.Name = t2.Name

Names              Employee Sales              
Maggie              1800                 
Colleen             2000                 
Laura               4000                 
Sean                1500

我正在寻找的结果：

Names              Employee Sales            
Maggie              1800                 
Colleen             2000                 
Laura               4000                 
Sean                 0 

select t2.Name, coalesce(t1."Employee Sales",0) "Employee Sales"
from emphis t2 left outer join
(select Name, sum(Sales) "Employee Sales"
from empdata
group by Name) t1
on t1.Name = t2.Name
where t1.Week = date_trunc('week', now())::date - 1

postgreSQL中的错误：

ERROR:  column t1.Week does not exist
LINE 7: where t1.Week = date_trunc('week', now())::date - 1

我用

where t1.Week = date_trunc('week', now())::date - 1

自动化，所以我不需要更改每个星期日的日期。

Answer 1

移动＆＃34;周＆＃34;子选择内的条件。这有两个好处：

如果有人在多个星期内有销售，您将获得该周的部分销售额。
如果他们没有销售额为$ 0

像这样：

select t2.Name,
    coalesce(t1."Employee Sales",0) "Employee Sales"
from emphis t2 
left outer join (
    select Name, 
        sum(Sales) "Employee Sales"
    from empdata
    where Week = date_trunc('week', now())::date - 1
    group by Name
    ) t1
on t1.Name = t2.Name

Answer 2

是的，因为您的子查询没有包含或选择Week列。您应该包括该列，例如

(select Name, sum(Sales) "Employee Sales", "Week"
from empdata
group by Name) t1
on t1.Name = t2.Name
where t1.Week = date_trunc('week', now())::date - 1

如果没有销售，则为零

2 个答案: