不同数据库SQL话语的差别
不同数据库SQL语句的差别
1，系统时间 Oracle：SYSDATE SQLSever：getdate() Access:date() 或者 now() 2，查询前n条记录 Oracel: Select * From (Select……) where rownum<=10 ((Select……)是要真正查询的语句) SQLServer:Select * From…………Top 10 MySql：Select * From tablename Limit 10 3, 随即抽取 MySql: FROM `table` AS t1 JOIN (SELECT ROUND(RAND() * ((SELECT MAX(id) FROM `table`)-(SELECT MIN(id) FROM `table`))+(SELECT MIN(id) FROM `table`)) AS id) AS t2 WHERE t1.id >= t2.id ORDER BY t1.id LIMIT 1;