查找数据表中互为配对记录的SQL查询需求

First, let's assume your table is named your_table (swap this out for your actual table name if it's different). Based on your data and requirements, here's a clean SQL query that will pull the exact paired records you're looking for:

SELECT t1.A, t1.B
FROM your_table t1
INNER JOIN your_table t2
    ON t1.A = t2.B 
    AND t1.B = t2.A;

How this works: #

• We use a self-join (joining the table to itself) to compare each row against every other row in the dataset.
• The join condition t1.A = t2.B AND t1.B = t2.A acts as a filter: it only keeps rows where there’s a matching "reverse" pair (so if row t1 has values (x,y), there must be a row t2 with (y,x)).

Testing with your sample data: #

For your provided rows:

This query will return exactly the pairs you expect:
(1,2), (2,1), (5,6), (6,5)

Rows like (2,3), (4,5), and (7,6) get excluded automatically—since there’s no corresponding reverse pair in the table, they don’t meet the join condition.

内容的提问来源于stack exchange，提问作者matei basar