年收入和支出表

Question

我有两个表收入（id，收入，日期，用户ID）和表费用(id,amount,date,userid)。现在我正在尝试创建一个收入总和，一年的金额总和的视图。它也必须是GROUPED by year和userid。

所以新表（视图）必须有收入，费用，年份的总和。现在我被困在这个代码上了。

SELECT
    id,
    i.Prihod,
    e.Rashod,
    YEAR
    YEAR(COALESCE(e.god, i.godi))) AS Godina , 
    users_id
FROM
    (
        SELECT 
            sum(insum) as 'Prihod',
            YEAR(datum) as 'Godi',
            users_id 
        FROM
        GROUP BY users_id
    ) as i
FULL OUTER JOIN
(
    SELECT 
        sum(amount) as 'Rashod',
        YEAR(datum) as 'God',
        users_id
    FROM expense
    GROUP BY users_id

) as e

Answer 1

这是结构化查询语言的结构化部分的工作。从三个子查询（虚拟表）开始。

第一：年份和用户列表。你需要这个，因为MySQL没有FULL OUTER JOIN功能。如果您正确编写此查询，则每个用户每年需要包含一行。

              SELECT DISTINCT YEAR(datum) Godi, users_id FROM income
              UNION
              SELECT DISTINCT YEAR(datum) Godi, users_id FROM expense

第二，按年份和用户的收入汇总。

               SELECT sum(insum) as Prihod,
                      YEAR(datum) as Godi,
                      users_id 
                 FROM income
                GROUP BY YEAR(datum), users_id

第三，按年和用户类似的费用总和

               SELECT sum(amount) as Rashod,
                      YEAR(datum) as God,
                      users_id 
                 FROM expense
                GROUP BY YEAR(datum), users_id

接下来，单独测试这些子查询，独立测试，以确保获得预期的结果。

最后，将它们连接在一起就像它们是表格一样，就像这样

SELECT yr.users_id, yr.Godi, inc.Prihod, exp.Rashod
  FROM (
              SELECT DISTINCT YEAR(datum) Godi, users_id FROM income
              UNION
              SELECT DISTINCT YEAR(datum) Godi, users_id FROM expense
       ) yr
  LEFT JOIN (
               SELECT sum(insum) as Prihod,
                      YEAR(datum) as Godi,
                      users_id 
                 FROM income
                GROUP BY YEAR(datum), users_id
       ) inc ON yr.users_id = inc.users_id AND yr.Godi = inc.Godi 
  LEFT JOIN (
               SELECT sum(amount) as Rashod,
                      YEAR(datum) as God,
                      users_id 
                 FROM expense
                GROUP BY YEAR(datum), users_id
       ) exp ON yr.users_id = exp.users_id AND yr.Godi = exp.God 

这里的查询模式是开发三个子查询。第一个确定最终结果集中的行数，因为它为每个所需行包含一行。对于最终结果集中所需的每一行，第二个和第三个查询都有一行或零行。然后你加入他们。