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sql sErvEr iFnull

isnull函数有的

如果是sqlserver ,用 isnull,如果是oracle,用nvl,mysql则用 ifnull UPDATE A set BYZD10 =(isnull(SELECT distinct(JF) FROM B where VIPBH=V_VIPSET.DM and fx='增加' and LX='99-期末'),0)+(isnull(SELECT distinct(JF) FROM B where VIPB...

StudentGirl() 返回的是数据表, 用select StudentGirl() 这样是输出单列值, 不是整张表的数据, 所以可以把 StudentGirl()直接当成一张表使用, 如: SELECT * FROM dbo.StudentGirl() WHERE ..... 可以加条件, 按照正常的查表语句都OK

--通用sql写法select case when 列 is null then 0 end--sql server写法select isnull(列,0)--Oracle 写法select nvl(name,0)

sqlserver中可用isnull函数: select isnull(null,'');oracle中可用nvl函数: select nvl(null,'') from dual;mysql中可用ifnull函数: select ifnull(null,'');

oracle select nvl(字段名,0) from 表名; sqlserver select isnull(字段名,0) from 表名;

距离table1 两列 a b,table2 两列 b,c select t1.*,(case when t2.c is null then 0 else t2.c end) as c from table1 t1 left join table2 t2 on(t1.b=t2.b)

SQL Syntax 1: IFNULL( expression, replacement ) Parameters: expression Any expression of any type. This expression is check for NULL. replacement The return value if the expression is NULL. Escape Syntax: {fn IFNULL( expression...

使用函数 nvl 举个栗子: 表1 id name liu 01 wang zhao 上表ID字段存在空值 select nvl(id,0),name from 表1 表1 id name 0 liu 01 wang 0 zhao

mysql: select ifnull(count(*),0)+0 as cc From dede_diyform3 where ifcheck=0sqlserver: select isnull(count(*),0)+0 as cc From dede_diyform3 where ifcheck=0挑着用吧

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