sql - T-SQL MERGE 与条件什么不匹配？

Question

假设我做了一个与条件匹配的合并

MERGE TargetTable WITH(HOLDLOCK) AS target
USING SourceTable AS source
ON (target.ID = source.ID)
WHEN MATCHED AND (source.BitCondition = 0) THEN
    UPDATE TargetTable
WHEN NOT MATCHED -- what is not matched??
    INSERT INTO TargetTable

不匹配的只是记录不在两个表中还是像

NOT(MATCHED AND (source.BitCondition = 0))

注意我有意忽略匹配且 BitCondition = 1 的情况

Answer 1

NOT MATCHED 的默认值根据 MERGE documentation是 NOT MATCHED BY TARGET ，表示该行存在于源中但不存在于 MERGE 的目标中.

避免使用 source.BitCondition = 1 插入不匹配的行，您可以添加 AND健康)状况:

WHEN NOT MATCHED BY TARGET AND (source.BitCondition = 0) THEN
    INSERT INTO TargetTable