select * form a
union all
select * form b
limit 0,10
查出来后,我想再人为加一个字段,标识这条记录是a还是b表的,应该怎么做
SELECT a.* ,
"A" AS `from_table`
FROM a
UNION ALL
SELECT b.* ,
"B" AS `from_table`
FROM b
LIMIT 0, 10
http://sqlfiddle.com/#!2/4d3379/2