1CREATETABLEtest4_01ASSELECTFROMpubstude
t_41WHERELENGTHsid12ANDLENGTH
ame2ANDd
ameISNOTNULLANDLENGTHd
ame3ANDLENGTHclass41完成学号不是12位，姓名长度小于2个字的院系名称为空值的，院系名称小于3个字的被跳过。deletefromtest4_01where
amelikeord
amelike2删除名字和院系名中带空格的deletefromtest4_01wherele
gthsex1deletefromtest4_01wheresexlike南3性别有误deletefromtest4_01whereage2012extractyearfrombirthday4出生日期和年龄不一致的deletefromtest4_01wheresidlikedeletefromtest4_01wheresidlikeA5学号中有非数字的（看了眼数据，感觉只有这两种，居然猜对了）【求助】学号中有非数字的正规思路怎么写？2createtabletest4_02asselectfrompubStude
t_course_42deletefromtest4_02wheretest4_02sid
oti
selectsidfrompubstude
t1学号在学生信息pubstude
t中不存在的deletefromtest4_02wheretest4_02cid
oti
selectcidfrompubcourse2课程号在课程信息pubcourse中不存在的deletefromtest4_02wheretest4_02tid
oti
selecttidfrompubteacher3教师编号在教师信息pubteacher中不存在的
createtablettasselectasidacidascoreatid
ffromtest4_02apubteacher_coursebwhereacidi
bcida
datidi
btiddroptabletest4_02createtabletest4_02asselectfromttdroptablett4有点混乱，先建一个临时表tt，把test4_02中“满足课程号和教师编号在教师授课表pubteacher_course中存在”的数据放到tt中，在drop掉test4_02，然后重新定义test4_02【求助】感觉不太正规，肯定有比这好很多的方法deletefromtest4_02wherescore
otbetwee
0a
d1005成绩数据有错误3createtablet1asselectdisti
ct
amefrompubstude
t去除重复的名字CREATETABLEtest4_03ASSELECTfirst_
ameCOUNTFreque
cyFROMSELECTSUBSTR
ame2LENGTH
ame1first_
ameFROMt1GROUPBYfirst_
ameDroptablet1一定要droptablet1这只是一个临时表，虽然一会还要用不过这是一个很好的习惯（ps：上一个答案的drop忘记复制了）4createtablet2asselectdisti
ct
amefrompubstude
tcreatetabletest4_04asSELECTletter，cou
tFreque
cyFROMSELECTSUBSTR
ame21letterFROMt2UNIONALLSELECTSUBSTR
ame31letterFROMt2WHERELENGTH
ame2GROUPBYletterDroptablet2
fr