is-null2.sql

本程序中即有讲义

use master 
go
create database mydb
go
use mydb
create table jobs
(jobid int primary key,
jobname char(10))
go
insert into jobs values (1,'aa')
insert into jobs values (2,null)
insert into jobs values (3,'')
go
select *from jobs
select count(jobname) from jobs
go
use master
go
drop database mydb