MySQL中提取10个随机行
SELECT column FROM table
ORDER BY RAND()
LIMIT 10
Oracle中提取10个随机行
SELECT column FROM ( SELECT column FROM table ORDER BY dbms_random.value ) WHERE rownum <= 10
PostgreSQL中提取10个随机行
SELECT column FROM table ORDER BY RANDOM() LIMIT 10
Microsoft SQL Server中提取10个随机行
SELECT TOP 10 column FROM table ORDER BY NEWID()
更新时间：2013-04-15
