取數據庫表前N條記錄，對於的SQL

/*取一表前N條記錄，各個數據庫的SQL寫法：
       1. Oracle             SELECT * FROM TABLE1 WHERE ROWNUM<=N
       2. DB2                SELECT * ROW_NUMBER() OVER(ORDER BY COL1 DESC) AS ROWNUM WHERE ROWNUM<=N
          DB2                SELECT COLUMN FROM TABLE FETCH FIRST N ROWS ONLY
       3. SQL Server         SELECT TOP N * FROM TABLE1
       4. MySQL:             select * from table_name limit N
/*獲取隨機記錄的前N條記錄

  1、db2:SELECT * FROM MYTABLE ORDER BY rand() DESC FETCH FIRST N ROWS ONLY
  2、sqlserver:SELECT top 10 * FROM userinf ORDER BY  NEWID()
  3、MySQL: select * from tablename order by rand() limit 10