select count(distinct b) from X_info where c=1;能放到一个CASE内么 不用where group by 等等因为有多个这样的case 所以 where 和groupby 都不能考虑.b是另一张表的主键.

select count和select count的区别 select count(*)count 什么意思和select * 有什么区别 select count(*) from 怎么使用 select count(1) from emp and select 4718 fromselect count select telnum,count(0),count(distinct othertelnum) from nmk.ljdx_cdr_temp group by telnum select Count(0) from MbrMember where 1=1Count(0)where 1=1 select count(*) from table1 select count(*) from table2 select count(*) from table3我从table1 table2 table3 中 找数据的条数怎样一下子用一条sql语句 算出TABLE1 TABLE2 TABLE3 记录的总和? select count (1)V_COUNT := 0;SELECT COUNT(1) INTO V_COUNT FROM CUST WHERE CUST_ID = ARG_CUST_ID;IF V_COUNT = 0 THEN我是个初学者,今有如上这么一段程序,里面select count(1)是什么意思? 机器上的英文字母是什么意思啊u: unit select key t: lare key n: count select key select id from (select id from pedigree group by number having count(name)>1)as a; 为啥用as a 这个能合并成一句吗?select count(ITEMKIND) from ITEM where ITEMKIND='1' ; select count(ITEMKIND) from ITEM where ITEMKIND='2 ;select count(ITEMKIND) from ITEM where ITEMKIND='3' ;select count(ITEMKIND) from ITEM where ITEMKIND='4' ; select co 手工注入时的语句 是什么意思啊 分可以加的select count(*) from adminselect count(*) from admin where len(username)>0) select count(*) from admin where len(password)>0) select count(*) from admin where len(username)=5) select count(*) SELECT select count(*) as total from 'test' order by id desc 希望得到正解 select a,b from 表名 group by a,b order by count(*) desc count count