MySQL-如何获取表A中表B中不存在的值的列表? [英] MySQL - How to get a list of values in Table A that don't exist in Table B?

问题描述

**Table A**
1
2
3
4
5
6


**Table B**
2
3
5

如何为仅在表B中存在的条目ID选择?在此示例中，我正在寻找一个返回1、4和6的查询.

How can I select for entry IDs that only exist in Table B? In this example, I'm looking for a query that returns 1, 4, and 6.

推荐答案

假定该列的名称为'id'，或者:

Assuming the column is named 'id', either:

SELECT *
FROM tableA a
WHERE NOT EXISTS (SELECT 1 FROM tableB WHERE id = a.id)

或

SELECT *
FROM TableA
WHERE id NOT IN (SELECT id FROM tableB)

您可能需要进行测试以查看效果最佳. MySQL可能有点不可预测.

You will probably need to test to see which performs best. MySQL can be a bit unpredictable.

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