mysql 8 上的聚合查询

Question

我有两个table，津贴和薪水，

津贴table看起来像，

Id  Title       value
1   Transport   2000
2   Housing     1000
3   Housing     1000

工资 table,

对于没有住房津贴的 id，对于住房，该值应被视为 0，并且应仅显示工资。如果有住房补贴，工资加住房。

我的查询没有给出正确的输出，

SELECT 
    s.id,
    CASE
        WHEN t.`Housing` = 0 THEN s.salary
    END AS Salary,
    CASE
        WHEN t.`Housing` <> 0 THEN t.Housing + s.salary
        WHEN t.`Housing` = 0 THEN  s.salary
    END AS SalaryAndHousing
FROM
    (SELECT 
        id,
            CASE
                WHEN Title = 'Housing' THEN value
                WHEN Title <> 'Housing' THEN 0
            END AS 'Housing'
    FROM
        Allowance) t
        JOIN
    Salaries s ON (t.id = s.id);

我的查询输出是，

id  Salary  SalaryAndHousing
1    2000        2000
2    null        2000
3    null        4000

它应该看起来像，

   id        Salary    SalaryAndHousing
    1         2000          2000 -- 2000 + 0
    2         1000          2000 -- 1000 + 1000
    3         3000          4000 -- 1000 + 3000

dbfiddle

Answer 1

这是一个非常简单的查询：

select 
    s.id,
    s.Salary,
    s.Salary + coalesce(a.value, 0) SalaryAndHousing
from Salaries s 
left join Allowance a on a.id = s.id and a.Title = 'Housing'
order by s.id;

在 SQLize.online

上试用

mysql 8 上的聚合查询

Aggregate query on mysql 8

mysql

mysql-8.0