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count()
SELECT (SELECT count(1) FROM ecs_category) as 'Export category count', (SELECT count(1) FROM ecs_goods) as 'Goods count', (SELECT count(1) FROM ecs_goods_attr) as 'Attr count'; </screen> </section> <section id="group_concat"> <title>group_concat() 列传行</title> <para></para> <screen><![CDATA[ SELECT tags FROM neo.article; linux redis mysql java php
tags字段专为一行显示
SELECT group_concat(tags) FROM neo.article; linux,redis,mysql,java,php
distinct 去除重复数据
select group_concat(distinct author) from neo.article;
以id分组,把name字段的值打印在一行,分号分隔
select id,group_concat(tags separator ';') from neo.article group by tags;
排序结果
select group_concat(distinct author order by author desc) from neo.article;