随机选择行的SQL语句? ORACLE SQLSERVER ECT.
MySQL:
SELECT column from table
ORDER BY RAND()
LIMIT 1
PostgreSQL:
SELECT column from table
ORDER BY RANDOM()
LIMIT 1
Microsoft SQL Server:
SELECT TOP 1 column from table
ORDER BY NEWID()
IBM DB2
SELECT column, RAND() as IDX
from table
ORDER BY IDX FETCH FIRST 1 ROWS ONLY
Thanks Tim
Oracle:
SELECT column from
( SELECT column from table
ORDER BY dbms_random.value )
WHERE rownum = 1
Thanks Mark Murphy
Feel free to post other example, variations, and SQL statements for other database servers in the comments.
相关文档:
一、 常用日期数据格式
1.Y或YY或YYY 年的最后一位,两位或三位
SQL> Select to_char(sysdate,'Y') from dual;
TO_CHAR(SYSDATE,'Y')
--------------------
7
SQL> Select to_char(sysdate,'YY') from dual;
TO_CHAR(SYSDATE,'YY')
---------------------
07
SQL> Select to_char(sysdate,'YYY') from d ......
select sid,
p1,
p1raw,
p2,
p2raw,
p3,
p3raw,
&n ......
SQL位运算
select 2|8 --10
select 2|8|1 --11
select 10&8 --8,包含,10=8+2
select 10&2 --2,包含,10=2+8
select 10&4 --0,不包含
select 19&16 --16,包含,19=16+2+1
s ......
Cross Apply使表可以和表值函数结果进行join, 这样表值函数的参数就可以使用一个结果集,而不是一个标量值,下面是book online的原文,有例子,有解释。
The APPLY operator allows you to invoke a table-valued function for each row returned by an outer table expression of a query. The table-valued function act ......
原文地址:http://www.cnblogs.com/changhai0605/articles/1276319.html
Oracle的请参考:http://zonghl8006.blog.163.com/blog/static/4528311520083995931317/
1.简介:
SQL Server 2005中新增的窗口函数帮助你迅速查看不同级别的聚合,通过它可以非常方便地累计总数、移动平均值、以及执行其它计算。
窗口函数功能非 ......