如何使用UNION从两个查询返回相同数量的行？

Question

我有两个使用SUM()和GROUP BY的查询。每个查询应返回相同的数字或行。在这种情况下，Sybase中的SQL会在同一行上单独返回行。这是我的查询：

SELECT type_id, category_id, category_name, type_code, amount, awarded
    FROM (
        SELECT
            type_id, 
            category_id,
            category_name, 
            type_code,
            CASE 
                WHEN category_id = 1 THEN SUM(amount)
                WHEN category_id = 2 THEN SUM(amount)
                WHEN category_id = 3 THEN SUM(amount)
                WHEN category_id = 4 THEN SUM(amount)
            END AS amount,
            0 AS awarded
        FROM Table 1
        GROUP BY category_id, type_id, category_id, type_code
        UNION
        SELECT
            null AS type_id, 
            ga.grant_category_id,
            '' AS category_name, 
            null AS type_code,
            0 AS amount,
            CASE 
                WHEN t2.category_id = 1 THEN SUM(t2.awarded)
                WHEN t2.category_id = 2 THEN SUM(t2.awarded)
                WHEN t2.category_id = 3 THEN SUM(t2.awarded)
                WHEN t2.category_id = 4 THEN SUM(t2.awarded)
            END AS awarded
        FROM Table2 t2
            INNER JOIN Table3 t3
                ON t2.rec_id = t3.rec_id
        GROUP BY t2.category_id
    ) x
    GROUP BY x.category_id

查询结果如下所示：

type_id  category_id  category_name  type_code   amount   awarded
   1         2             TEST 2      REST     51804.00    0.00
   1         4             TEST 4      REST     39398.00    0.00
   1         3             TEST 3      REST     79922.00    0.00
   1         1             TEST 1      REST     70927.00    0.00
  null       1             null        null       0.00     96013.00
  null       2             null        null       0.00     78759.00
  null       3             null        null       0.00     21436.00
  null       4             null        null       0.00     74602.00

我希望输出看起来像这样：

 type_id  category_id  category_name  type_code   amount   awarded
   1         2             TEST 2      REST     51804.00    96013.00
   1         4             TEST 4      REST     39398.00    78759.00
   1         3             TEST 3      REST     79922.00    21436.00
   1         1             TEST 1      REST     70927.00    74602.00

如何实现这个输出？谢谢。

Answer 1

当@Gordon谈到JOIN时，他的意思是让它们成为子查询并加入它们。以下假设任何一个查询都可以返回或不返回类别：

SELECT
   Set1.type_id  --  Where this is not found in Set1, you specified null in Set2
  ,ISNULL(Set1.category_id, Set2.grant_category_id)  AS  category_id
  ,ISNULL(Set1.category_name, '')  --  Where this is not found in Set1, you specified <emptyString> in Set2
  ,Set1.type_code  --  Where this is not found in Set1, you specified null in Set2
  ,ISNULL(Set1.amount, 0)  --  Where this is not found in Set1, you specified 0 in Set2
  ,ISNULL(Set2.awarded, 0)  --  Where this is not found in Set2, you specified 0 in Set1
 FROM (
        SELECT
            type_id, 
            category_id,
            category_name, 
            type_code,
            SUM(CASE 
                    WHEN category_id between 1 and 4 THEN amount
                    ELSE 0
                END) AS amount
        FROM Table1
        GROUP BY
            type_id, 
            category_id,
            category_name, 
            type_code,
      ) Set1
 FULL OUTER JOIN (   
        SELECT
            t2.grant_category_id,
            SUM(CASE 
                    WHEN t2.category_id between 1 and 4 THEN t2.awarded
                END) AS awarded
        FROM Table2 t2
            INNER JOIN Table3 t3
                ON t2.rec_id = t3.rec_id
        GROUP BY
            t2.grant_category_id,
    ) Set2
  ON Set2.grant_category_Id = Set1.category_id

免责声明：我无法检查此语法，因此可能需要进行一些小调试。

Answer 2

那是你要的吗？

SELECT type_id, category_id, category_name, type_code, amount, awarded
    FROM (
        SELECT
            t1.type_id, 
            t1.category_id,
            t1.category_name, 
            t1.type_code,
            SUM(t1.amount) amount,
            SUM(t2.awarded) awarded
        FROM Table1 t1
            INNER JOIN Table2 t2
                ON t1.category_id = t2.category_id
            INNER JOIN Table3 t3
                ON t2.rec_id = t3.rec_id
        GROUP BY 
            t1.type_id, 
            t1.category_id,
            t1.category_name, 
            t1.type_code
        )    x

而且，在你的例子中，我觉得有一个错误。不应该那样吗？表1和表2的键是category_id

type_id category_id category_name type_code金额奖励 1 2 TEST 2 REST 51804.00 78759.00 1 4 TEST 4 REST 39398.00 74602.00 1 3 TEST 3 REST 79922.00 21436.00 1 1 TEST 1 REST 70927.00 96013.00