VARCHAR上的INNER JOIN [英] INNER JOIN on VARCHAR

问题描述

即使两个表包含多个匹配值，以下查询也会返回0行.

The following query returns 0 rows, even though the two tables contain several matching values.

SELECT i.isrc, m.isrc FROM table1 i INNER JOIN table2 m ON i.isrc = m.isrc;

由于isrc列是varchar类型，我怀疑这可能与表排序规则有关.但是，将两种排序规则都更改为utf-8并不能解决问题.

Because the isrc column is a varchar type, I suspected it might be a problem with the table collation. Changing both collations to utf-8, however, did not fix the problem.

这里可能是什么问题?

推荐答案

尝试以下操作，

SELECT i.isrc, m.isrc 
FROM table1 i 
INNER JOIN table2 m
ON UPPER(TRIM(i.isrc)) = UPPER(TRIM(m.isrc))

注意:

1. 修剪两侧的值
2. 规范案例

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