create table msg_mobile
(mobile varchar(20), 
Msg varchar(100), 
state varchar(20), 
sendyorn varchar(20), 
sendtime datetime, 
id int not null identity(1,1) primary key, 
senduser varchar(20), 
CommPort varchar(10))

insert into msg_mobile (mobile,Msg,sendtime) values('13000010001','test',getdate())

select * from msg_mobile

create  TRIGGER [dbo].[trg_msg_mobile_insert] ON [dbo].[msg_mobile] 
FOR INSERT
AS
    
    if (select count(*) from msg_mobile
        where exists
        (select * from inserted
            where inserted.mobile = msg_mobile.mobile
            and datediff(day,inserted.sendtime,msg_mobile.sendtime) = 0
            and inserted.msg = msg_mobile.msg)) >1
    begin
        raiserror 99999 '不能在同一天给同一用户发送同一内容的短信！'
        rollback tran
        return 
    end
    
insert into msg_mobile (mobile,Msg,sendtime) values('13000010001','test',getdate())    

select * from msg_mobile
/****
消息 99999，级别 16，状态 1，过程 trg_msg_mobile_insert，第 12 行
不能在同一天给同一用户发送同一内容的短信！
消息 3609，级别 16，状态 1，第 1 行
事务在触发器中结束。批处理已中止。
***/
insert into msg_mobile (mobile,Msg,sendtime) values('13000010001','test',getdate())    
insert into msg_mobile (mobile,Msg,sendtime) values('13000010002','test',getdate())    
insert into msg_mobile (mobile,Msg,sendtime) values('13000010002','test',getdate())    
insert into msg_mobile (mobile,Msg,sendtime) values('13000010003','test',getdate())    
insert into msg_mobile (mobile,Msg,sendtime) values('13000010003','test',getdate())    


drop table msg_mobile

------解决方案--------------------
将发送成功的消息内容+手机号+发送日期保存下来,发送时按消息内容+手机号+发送日期查一下,有记录的不发送

------解决方案--------------------
是的，否则如何实现你的要求？