sql存在该记录就更新,不存在就插入

数据库：

CREATE TABLE aa

(

user_id INT UNSIGNED NOT NULL,

visit_times INT UNSIGNED NOT NULL,

PRIMARY KEY(user_id)

);

mysql 写法：

insert into aa(user_id,visit_times)values(1,1)ON DUPLICATE KEY UPDATE visit_times=visit_times+1;

sql server 写法：

 

if not exists (select * from test where user_id= 1)   
insert into test(user_id, visit_times) values(1, 1) 
else    
update test set visit_times = visit_times + 1 where user_id= 1