在不同数据库环境下读取前N条记录数：

1. Oracle

Select * FROM TABLE1 Where ROWNUM<=N

2. Informix

Select FIRST N * FROM TABLE1 where 1=1

3. MySQL

Select * FROM TABLE1 where 1=1 LIMIT N

4. DB2

Select * ROW_NUMBER() OVER(ORDER BY COL1 DESC) AS ROWNUM Where ROWNUM<=N

或者

Select COLUMN FROM TABLE where 1=1 FETCH FIRST N ROWS ONLY

5.SQL Server

Select TOP N * FROM TABLE1 where 1=1

or

SET ROWCOUNT N Select * FROM TABLE1 where 1=1 SET ROWCOUNT N1

6. Sybase

SET ROWCOUNT N Select * FROM TABLE1 where 1=1 SET ROWCOUNT N1

7. FOXPRO

Select * TOP N FROM TABLE orDER BY COLUMN

8. ACCESS

Select TOP N * FROM TABLE1 where 1=1