mysql中如何将2张表联立排序？

2张表关联排序,用union来做.

SELECT * FROM (SELECT id,ach,'X' AS counter,'A' AS class,date FROM tablename1 as t1 WHERE 1 UNION SELECT id,ach,counter,'B' AS class,date FROM tablename2 as t2 WHERE 1) AS tall order by date asc

建议增加条件,且为索引字段.其次查的数据量不能太大,不然临时表会占据较多的内存空间.宁可牺牲硬盘空间,也不要无谓的牺牲内存空间.

从长远角度来说,建议整合2个表.

SELECT

a.name,b.name

FROM

blog_index

a

INNER

JOIN

news_index

b

ON

a.xx=b.xx

xx是用来连接a和b的字段名

如果连接两个表的字段名是一样的可以简写为

SELECT

a.name,b.name

FROM

blog_index

a

INNER

JOIN

news_index

b

USING(xx)

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