¡¾Ð¡Ð¡ÎÊÌ⼯½õ13Ö® ¹ØÓÚ·Ö×é¼Ó˳ÐòºÅµÄSQLд·¨¡¿
/*
Ô±í£º
thid other
a 1
a 1
b 0
b 0
b 0
c 2
c 2
Ï£Íû±ä³É£º
thid other
a 1
a 2
b 0
b 1
b 2
c 2
c 3
*/
if OBJECT_ID('tb') is not null
drop table tb
go
create table tb (id varchar(10) ,value int)
insert tb select
'a' , 1 union all select
'a' , 1 union all select
'b' , 0 union all select
'b' , 0 union all select
'b' , 0 union all select
'c' , 2 union all select
'c' , &nb
Ïà¹ØÎĵµ£º
SQL±¦µä
SQL±ØÖª±Ø»áµÚÈý°æ
SQLÈëÞµäµÚËİæ
Sams Teach Yourself SQL in 10 Minutes Third Edition
SQL The Complete Reference
......
Ò»£ºSelectÓï¾ä£º
select ×Ö¶ÎÃû from ±íÃû where Ìõ¼þ order by ÅÅÐò
see:select distinct ´Ó¶à¸öÏàͬ×Ö¶ÎÖÐץΨһֵ
see:²éÕÒld_det_andy±íÖÐÓÐÊý¾Ýµ«ld_det_temp±íÖÐûÊý¾ÝµÄÊý¾Ý
select * from ld_det_a ......
ÓÐʱÔÚ×ö³ÌÐòʱ£¬²âÊÔʱµÄÊý¾Ý£¬ÒªÄÃÏñÓû§ÑÝʾ£¬Êý¾Ý¿âµÄ¸½¼ÓÊÇ×îÖ±½ÓµÄ°ì·¨£¬µ«Èô´ÓSQL Server 2005תÏò2000µ¼³öÂé·³£¬ÄÚÈÝÒ²¶à£¬Éú³ÉSQLÓï¾äÊÇ×îºÃµÄ°ì·¨£¬Ò²ÊÇÔÚÍøÉÏÕҵŤ¾ß,mssql2µ¼³ö·Ç³£·½±ã£¬µ£ÐÄÎÒÒÔºóÄѵÃÕÒËùÒÔ·ÅÔÚÕâÀÒÔ±¸ºóÓᣠ......
select *from student
select student_id from student
select student_id ,student_name from student
select student_id student_name from student ½«student_name ×÷Ϊstudent_idµÄ±ðÃû´¦Àí
È磺 select student_id a from student
select a=student_id from student
´Óstudent±íÖзֱð¼ ......
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 ......