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mysql count group by统计条数解决方案
2020-11-05 15:02:00mysql count group by统计条数方法mysql 分组之后如何统计记录条数 mysql 分组之后如何统计记录条数 mysql 分组之后如何统计记录条数? gourp by 之后的 count, 把group by查询结果当成一个表再count一次 select ... -
mysql count group by统计条数方法
2018-11-07 10:32:19mysql count group by统计条数方法 mysql 分组之后如何统计记录条数? gourp by 之后的 count,把group by查询结果当成一个表再count一次 select count(*) as count from (SELECT count(*) FROM 表名 WHERE 条件 ...mysql count group by统计条数方法
mysql 分组之后如何统计记录条数? gourp by 之后的 count,把group by查询结果当成一个表再count一次
select count(*) as count from
(SELECT count(*) FROM 表名 WHERE 条件 GROUP BY id ) a;实战例子:
select
count(*) as total
from (select count(*) from users group by user_id) u转载:流风,飘然的风,博客网站:http://www.ssqhm.com
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mysql分组后查询条数_MySQL分组后,如何统计记录条数
2021-01-19 10:49:26MySQL分组后,统计记录条数的方法:1、统计记录条数,代码为【SELECT num,count(*) AS counts from test_a GROUP BY num】;2、对num去重后的数量的统计。MySQL分组后,统计记录条数的方法:分组后,统计记录条数:...MySQL分组后,统计记录条数的方法:1、统计记录条数,代码为【SELECT num,count(*) AS counts from test_a GROUP BY num】;2、对num去重后的数量的统计。
MySQL分组后,统计记录条数的方法:
分组后,统计记录条数:SELECT num,count(*) AS counts from test_a GROUP BY num;
查询结果如下:
对num去重后的数量的统计:SELECT count(t.counts) FROM ( SELECT num,count(*) AS counts from test_a GROUP BY num ) AS t;
SELECT count(DISTINCT num) AS count FROM test_a;
它俩结果一样,都是5;只是一个是子查询(嵌套),一个是内置函数 distinct();
数据库结构
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