SQL:INSERT INTO ... VALUES..SELECT

Question

如果从TableX获取colA的值,从TableY获取colB值,从TableZ获取colC,如何编写INSERT语句？

例如:INSERT INTO TableA(colA,colB,colC)VALUES(？,？,？)

任何想法,如果有可能吗？

Answer 1

INSERT INTO TableA(colA, colB, colC)
  SELECT TableX.valA, TableY.valB, TableZ.valC
    FROM TableX
   INNER JOIN TableY ON :......
   INNER JOIN TableZ ON ........

当然,TableX,TableY和TAbleZ也可能以其他方式相关(不是INNER JOIN).

如果你无法找到所有表之间的任何关系,你也可以分别做三个

SELECT @value1 = valA FROM TableX WHERE ......
SELECT @value2 = valB FROM TableY WHERE ......
SELECT @value3 = valC FROM TableZ WHERE ......

然后是这样的插入:

INSERT INTO TableA(colA, colB, colC)
             VALUES(@value1, @value2, @value3)

这是最终的最后手段,你不能在一个SELECT声明中表达一切.

渣

Answer 2

为了回应marc_s的答案,您可以从以下选择中的不相关表中查询:

INSERT INTO TableA
    (colA, colB, colC)
SELECT
    (SELECT valA FROM TableX WHERE ...),
    (SELECT valB FROM TableY WHERE ...),
    (SELECT valC FROM TableZ WHERE ...)