mysql中的if函数怎么用

IF(expr1,expr2,expr3)

mysql> select name,if(sex=0,'女','男') as sex from student;

+-------+-----+

| name  | sex |

+-------+-----+

| name1 | 女  |

| name2 | 女  |

| name3 | 男  |

| name4 | 女  |

+-------+-----+

rows in set (0.00 sec)

SELECT  s.SCHOOL_CITY as schoolCity,

        s.SCHOOL_COUNTY as schoolCounty,

        count(DISTINCT `s`.`SCHOOL_ID`) as schoolNum,

        sum(m.duration) as sumDuration,

        sum(`m`.`VIEWERCOUNT`) as viewLiveSum,

        sum(m.replayViewerCount)as reViewSum,

        sum(m.praisecount) as sumpraise,

        sum(`m`.`VIEWERCOUNT`+m.replayViewerCount) as viewSum

         from ((tbl_hbb_mobile_live_statistics m join tbl_hbb_resource_visit_map v) join tbl_school_info s)

    where`m`.`RESOURCEID`= `v`.`RESOURCEID`

        and if((`v`.`rangeTYPE`= '2'),(`v`.`rangeID`= `s`.`SCHOOL_ID`),(`v`.`parentId`= `s`.`SCHOOL_ID`))