Ëæ»úÑ¡ÔñÐеÄSQLÓï¾ä? 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.
Ïà¹ØÎĵµ£º
Ò»¡¢ ³£ÓÃÈÕÆÚÊý¾Ý¸ñʽ
1.Y»òYY»òYYY ÄêµÄ×îºóһ룬Á½Î»»òÈýλ
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 ......
¾²âÊÔ£¬ÔÚOracleÖУ¬¶ÔÓÚnullºÍ¿Õ×Ö·û´®'',webMethods JDBC Adapter ²éѯ³öÀ´¶¼»áÏÔʾnull.
¶øÔÚSQL SERVERÖУ¬»á·Ö±ðÏÖʵΪnullºÍ¿Õ×Ö·û´®¡£
º¬Òå½âÊÍ£º
ÎÊ£ºÊ²Ã´ÊÇNULL£¿
´ð£ºÔÚÎÒÃDz»ÖªµÀ¾ßÌåÓÐʲôÊý¾ÝµÄʱºò£¬Ò²¼´Î´Öª£¬¿ÉÒÔÓÃNULL£¬ÎÒÃdzÆËüΪ¿Õ£¬ORACLEÖУ¬º¬ÓпÕÖµµÄ±íÁ㤶ÈΪÁã¡£
ORACLEÔÊÐíÈκÎÒ»ÖÖÊý¾ ......
ÒÔsystemµÇ¼½øÈ¥Ö®ºó£¬Ö´ÐÐÏÂÃæµÄÃüÁ
SQL> alter user scott account unlock; £¨Íê³É½âËøµÄ²Ù×÷£©
Óû§ÒѸü¸Ä¡£
SQL> alter user scott identified by tiger; £¨ÖØÐ¸øscottÕâ¸öÓû§É趨ÃÜÂ룩
Óû§ÒѸü¸Ä¡£
SQL> conn scott/tiger
ÒÑÁ¬½Ó¡£ ......
SQLλÔËËã
select 2|8 --10
select 2|8|1 --11
select 10&8 --8,°üº¬,10=8+2
select 10&2 --2,°üº¬,10=2+8
select 10&4 --0,²»°üº¬
select 19&16 --16,°üº¬,19=16+2+1
s ......
Êý¾Ý¿âµÄÐÔÄܲâÊÔ¿ÉÒÔ°ïÖúÄãÌáǰ֪µÀÄãµÄϵͳµÄ¸ºÔØÄÜÁ¦£¬¿ÉÒÔ°ïÖúÄã¸Ä½øÏµÍ³µÄʵʩ»òÉè¼Æ£¬¿ÉÒÔ°ïÖúÄãÈ·¶¨Ò»Ð©Éè¼ÆºÍ±à³ÌÔÔò. µ«ÊÇ£¬ÕâÀïÃæÒ²ÓÐÏÝÚå. Èç¹û²»Ð¡ÐÄ£¬Äã»á×Ô¼º°Ñ×Ô¼ºÏݽøÈ¥£¬È´×îÖÕ²»Ã÷°×ÊÇʲôÔÒò. ÕâÀÎÒÄÃһλÏÈÉúΪÀý£¬À´¿´¿´ËûÔõô×Ô¼º°Ñ×Ô¼º¸ãºýÍ¿µÄ.
×î½ü, ÏëÆðÔÚ´æ´¢¹ý³ÌÖо¿¾¹ÊÇʹÓÃÁÙʱ±í»¹ÊÇÊ ......