SQL重复数据的提取与过滤
提取重复数据
SELECT * FROM tablename GROUP BY colname HAVING COUNT(*) > 1
www.2cto.com
过滤重复数据
SELECT * FROM tablename GROUP BY colname HAVING COUNT(*) = 1
SQL重复数据的提取与过滤
SQL重复数据的提取与过滤
SQL重复数据的提取与过滤