1.产生一个结果集,如果一个员工工资小于等于2000,就返回消息“NO”,如果大于等于4000,就返回消息“YES”。如果在这两者之间,就返回“OK”.结果集如下:EMP
表
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原始数据Namesal------------------------------Wsp2300Hjj6700king6000ford1800james1200按要求,显示效果图Namesalstatus------------------------------------------Wsp2300okHjj6700yesking6000yesford1800nojames1200noselectName,sal,caseWHENsal<=2000THEN"NO"WHENsal>=4000THEN"YES"ELSE"OK"endasstatusFROMEMP;2.从表中随机返回5条记录!可以修改下面的语句,要求下次执行时产生不同的结果集Selectename,jobfromempSelectename,jobfromemporderbyrand()limit5;3.如:emp表Deptnocnt------------------------------103205306效果图:Deptno_10Deptno_20Deptno_30---------------------------------------------------356SELECTSUM(CASEWHENDeptno=10THEN3ELSE0END)asDeptno_10,SUM(CASEWHENDeptno=20THEN5ELSE0END)asDeptno_20,SUM(CASEWHENDeptno=30THEN6ELSE0END)asDeptno_30FROMemp;4.如表emp原台数据如empnojobname-------------------------------------------------------------1analystscott2analystford3clearksmith4clearkmiller5clearkjames6managerjones7managerclark8managerblank效果图:Clearkmanageranalyst----------------------------------------------SmithjonesscottMillerclarkfordJamesblankSELECTMAX(IF(job='cleark',name,''))AScleark,MAX(IF(job='manager',name,''))ASmanager,MAX(IF(job='analyst',name,''))ASanalystFROMempGROUPBYnameORDERBYnameDESC