Question

我想要一个查询来计算列中的重复值，是否有任何查询，或者我认为是

total records=SELECT COUNT(column_name) FROM table_name;
distinct records=SELECT COUNT(DISTINCT column_name) FROM table_name;
duplicate count=total records-distinct records;

Answer 1

查看你的sql，它可以简化如下：

SELECT Count(Column) - Count(DISTINCT Column)
FROM   yourTable

Answer 2

差不多，是的。您可以在一个查询中执行此操作：

SELECT (SELECT COUNT(col) FROM tbl) - (SELECT COUNT(DISTINCT col) FROM tbl);

编辑：NoDisplayName的好点。这至少适用于MySQL，我不保证跨引擎的兼容性（我上次在十五年前在Oracle上工作过，而且从不在SQL Server上工作）

Answer 3

select column_name, count(*) 
from table_name 
group by column_name 
having count(*) > 1

Answer 4

你可以试试这个：

SELECT COUNT(column_name) as count 
   FROM table_name 
  GROUP BY column_name 
 HAVING count > 1

计算列sql中的重复值

4 个答案: