Question

SELECT 
    tableA.col1,
    tableA.col2,
    LEFT(tableB.col3, 4) as person

FROM tableA

LEFT JOIN tableB ON

    tableB.col1 = tableA.col1 AND
    tableB.col2 = tableA.col2

WHERE tableA.col3 = '000000'

AND tableA.col4 <> ''

AND person = 'Zeus'

ORDER BY tableA.col1, tableA.col4 ASC;

---

col1          col4        person
001           abc         Zeus
002           abc         Zeus
003           xyz         Zeus
004           xyz         Zeus

+

SELECT
    tableC.col1,
    SUM(tableC.col2) as cost

FROM tableC

WHERE tableC.col3 = 'L'

GROUP BY tableC.col1, tableC.col3;

---

col1          cost
001           23462
002           25215
003           92381
004           29171

=

col1          col4          person          cost
001           abc           Zeus            23462
002           abc           Zeus            25215
003           xyz           Zeus            92381
004           xyz           Zeus            29171

我该怎么做？我尝试将第二个查询作为嵌套选择放在顶部查询中，但我无法使其工作。两个结果集共享相同的col1值，这是唯一的，所以我想他们需要加入它？最终person是每次运行时查询都会有所不同的地方。

Answer 1

您可以尝试使用col1上的内连接

SELECT tableA.col1, tableA.col2, LEFT(tableB.col3, 4) as person, tableC.col1, SUM(tableC.col2) as cost
FROM tableA
LEFT JOIN tableB ON ( tableB.col1 = tableA.col1 AND tableB.col2 = tableA.col2)
INNER JOIN tableC ON ( tableA.col1 = tableC.col1)
WHERE tableA.col3 = '000000'
AND tableA.col4 <> ''
AND person = 'Zeus'
GROUP BY tableA.col4, person, tableC.col1, tableC.col3;
ORDER BY tableA.col1, tableA.col4 ASC;

Answer 2

如果您不想组合查询，可以为查询设置别名，例如此查询

select * from example ... as table1;

并且您在table1中有选择结果，因此您可以在问题中为其他选择设置别名

SELECT
    tableC.col1,
    SUM(tableC.col2) as cost

FROM tableC

WHERE tableC.col3 = 'L'

GROUP BY tableC.col1, tableC.col3 as table2

现在您可以在问题中的table1和table上使用join或其他命令

join can give you preffered result.
SELECT 
    table1.*,
    table2.*   
FROM table1
JOIN table2 ON
    table1.col1 = table2.col1
ORDER BY table1.col1

需要帮助组合SQL查询

2 个答案: