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sql判断值为null:SQL 空值NULL 判断办法

create database test go use test go create table test123 ( id int, word varchar(50), ) go insert into test123 (id,word)values(1,'1') insert into test123 (id,word)values(2,'2') insert into test123 (id,word)values(3,'3') insert into test123 (id,word)values(4,'4') insert into test123 (i [阅读全文] [PDF]