如何在不存在的地方进行插入? [英] How can I do an insert where not exists?

问题描述

我想将插入查询与不存在的地方"结合起来，以免违反 PK 约束.但是，如下所示的语法给了我一个 Incorrect syntax near the keyword 'WHERE' 错误 -

I'd like to combine an insert query with a "where not exists" so as not to violate PK constraints. However, syntax such as the following gives me an Incorrect syntax near the keyword 'WHERE' error -

INSERT INTO myTable(columns...)
VALUES(values...)
WHERE NOT EXISTS
   (SELECT *
    FROM myTable
    WHERE pk_part1 = value1,
        AND pk_part2 = value2)

我怎样才能做到这一点?

How can I accomplish this?

(一般来说，你可以将插入与 where 子句结合起来吗?)

(In general, can you combine an insert with a where clause?)

推荐答案

INSERT INTO myTable(columns...)
Select values...
WHERE NOT EXISTS
   (SELECT *
    FROM myTable
    WHERE pk_part1 = value1,
        AND pk_part2 = value2)

阅读马丁斯链接后，如果承认，最好的解决方案是:

After reading martins link, If admit, that the best solution is:

BEGIN TRY
    INSERT INTO myTable(columns...)
    values( values...)
END TRY
BEGIN CATCH
    IF ERROR_NUMBER() <> 2627
      RAISERROR etc
END CATCH;

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