Sql查询加入查询结果

Question

我有一个查询结果为：

Wname    NewCases
Mon       2
Tues      1
Sat       3

第二次查询结果为：

Wname     FollowUp
Tues         3
Wed          4
Friday       2

我需要编写 mysql 查询以获得如下结果：

Wname   NewCases   FollowUp
Mon       2          0
Tues      1          3
Wed       0          4
Fri       0          2
Sat       3          0

我的第一个查询：

Select   substring(dayname(Dated),1,3) as wname,
         count(RegId) as NewCases 
from     patienttable 
where    Patient_Type='New' 
     and week(Dated)=week(now()) 
group by dayname(Dated) 
order by Dated

第二次查询：

Select   substring(dayname(Dated),1,3) as wname,
         count(RegId) as FollowUp
from     patienttable
where    Patient_Type='FollowUp' 
     and week(Dated)=week(now()) 
group by dayname(Dated)
order by Dated

Answer 1

没有必要加入查询。
您可以使用条件聚合在一个查询中完成：

SELECT SUBSTRING(DAYNAME(Dated), 1, 3) AS wname,
       SUM(Patient_Type = 'New') AS NewCases,
       SUM(Patient_Type = 'FollowUp') AS FollowUp  
FROM patienttable 
WHERE Patient_Type IN ('New', 'FollowUp') AND WEEK(Dated) = WEEK(NOW()) 
GROUP BY DAYNAME(Dated);

Sql查询加入查询结果

Sql query to join query results

mysql

sql

group-by

sum

conditional-aggregation