Question

我有一个下面详细介绍的SQL，并希望有人可以帮助我优化这一点，因为我觉得它有点笨拙......感谢任何帮助，谢谢。

SELECT * FROM test.datalist
Where UserName Like '%SearchString%'
Or UserName In (
                Select Synonym
                From synonyms
                Where Synonym Like '%SearchString%'
                OR ListRef = (  Select ListRef 
                                From synonyms
                                Where Synonym Like '%SearchString%')
                );

感谢所有建议。

Answer 1

如果您已经与Where Synonym Like '%SearchString%'匹配，则子查询的下半部分没有任何意义，无法找到同一个表的ListRef来获取Synonym

Where Synonym Like '%SearchString%'
OR ListRef = (  Select ListRef 
                                From synonyms
                                Where Synonym Like '%SearchString%')

另外你可以尝试加入

SELECT * FROM datalist d
JOIN synonyms s ON (d.UserName =s.Synonym)    
Where d.UserName Like '%SearchString%' or s.Synonym Like '%SearchString%'

我已根据d.UserName =s.Synonym加入您的表格，如果您在这些表格之间存在特定关系，则应用该表格，并为您的列添加适当的索引

优化我的三级MySQL查询

1 个答案: