mysql条件查询if case 用法详解

select * from news where DATE(adddate) between
'2011-04-20' - INTERVAL 5 DAY and '2011-04-20' + INTERVAL 5 DAY
  

select * from news where DATE(adddate) in ('2011-04-20','2011-04-15','2011-04-25')

 DROP  PROCEDURE  IF EXISTS   过程名;
CREATE   PROCEDURE  过程名( 
    IN     trueName           VARCHAR(100),        
    IN     phone             VARCHAR(100),          
    IN     qqmsn              VARCHAR(100),          
    IN     mail               VARCHAR(100),         
    IN     mac               VARCHAR(100),        
    IN     heartip           VARCHAR(100)          
    )
    NOT DETERMINISTIC
    SQL SECURITY DEFINER
    COMMENT ''
BEGIN  
SELECT count(id) INTO @maccount  from `表名` where `表名`.mac=mac; --是否存在此记录
 if (@maccount>0) THEN
 update  `表名`  set `trueName`=trueName,`phone`=phone,`qqmsn`=qqmsn,`mail`=mail,`mac`=mac,

`heart`=`heart`+1,`heartip`=heartip,`heartdatetime`=CURRENT_TIMESTAMP WHERE 表

名.mac=mac;
ELSE
insert into `表名` (`trueName`,`phone`,`qqmsn`,`mail`,`mac`,`heartip`,`heartdatetime`)VALUES(trueName,phone,qqmsn,mail,mac,heartip,CURRENT_TIMESTAMP);
end IF;
END

select substr(t1.area_id, 1, 1) type,
       substr(t1.area_id, 2) id,
       case substr(t1.area_id, 1, 1)
         when 'c' then
          (select t2.country
             from countnumber.dbtable_countryid t2
            where t2.id = substr(t1.area_id, 2))
         else
          (select distinct t3.province
             from countnumber.dbtable_provinceid t3
            where t3.id = substr(t1.area_id, 2))
       end name
  from t_ad_area t1

mysql> SELECT CASE 1 WHEN 1 THEN 'one'

    ->     WHEN 2 THEN 'two' ELSE 'more' END;

        -> 'one'

mysql> SELECT CASE WHEN 1>0 THEN 'true' ELSE 'false' END;

        -> 'true'

mysql> SELECT CASE BINARY 'B'

    ->     WHEN 'a' THEN 1 WHEN 'b' THEN 2 END;

        -> NULL