MSSQL - 仅当所有值都不为空时才插入值

Question

所以我有这个查询

"INSERT INTO tblAssetRelations (ParentAssetID, ChildAssetID, Type)
VALUES (
    (SELECT tblAssets.AssetID FROM tblAssets WHERE tblAssets.AssetName = $field2),
    (SELECT tblAssets.AssetID FROM tblAssets WHERE tblAssets.AssetName = $field1),
    12
    );"

如果 VALUES 中的 SELECT 语句之一没有返回值（null），我如何取消/中止 INSERT 语句

ps：$field1 和 $field2 是 powershell 脚本的变量

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这样的东西会起作用吗？我不确定语法。

declare @Variable1, @Variable2;

set @Variable1 = SELECT tblAssets.AssetID FROM tblAssets WHERE tblAssets.AssetName= $field2
set @Variable2 = SELECT tblAssets.AssetID FROM tblAssets WHERE tblAssets.AssetName= $field1
 
 if @Variable1 IS NOT Null AND @Variable2 IS NOT Null 
    INSERT INTO tblAssetRelations (ParentAssetID, ChildAssetID, Type)
    VALUES (@Variable1, @Variable2, 12);

Answer 1

您可以尝试使用INSERT INTO ... SELECT 语句：

INSERT INTO tblAssetRelations (ParentAssetID, ChildAssetID, Type)
SELECT a, b, c FROM (
  SELECT
    (SELECT tblAssets.AssetID FROM tblAssets WHERE tblAssets.AssetName = $field2) AS a,
    (SELECT tblAssets.AssetID FROM tblAssets WHERE tblAssets.AssetName = $field1) AS b,
    12 AS c
  ) WHERE a IS NOT NULL AND b IS NOT NULL

然后你会用WHERE a IS NOT NULL AND b IS NOT NULL中止INSERT