SQL-查询前N条记录

1. 不同数据库中查询前N条记录 

数据库类型	SQL
oracle	select * FROM table1 Where ROWNUM<=N;
db2	select * ROW_NUMBER() OVER(ORDER BY COL1 DESC) AS ROWNUM Where ROWNUM<=N  或者 select COLUMN FROM TABLE FETCH FIRST N ROWS ONLY
mysql	select * FROM table1 LIMIT N
mssql	select TOP N * FROM table1
postgresql	select * FROM TABLE LIMIT  n