精妙的SQL語(yǔ)句第1/2頁(yè)
發(fā)布日期:2022-02-05 12:56 | 文章來(lái)源:站長(zhǎng)之家
select*intobfromawhere1<>1
說(shuō)明:拷貝表(拷貝數(shù)據(jù),源表名:a目標(biāo)表名:b)
insertintob(a,b,c)selectd,e,ffromb;
說(shuō)明:顯示文章、提交人和最后回復(fù)時(shí)間
selecta.title,a.username,b.adddatefromtablea,(selectmax(adddate)adddatefromtable
wheretable.title=a.title)b
說(shuō)明:外連接查詢(xún)(表名1:a表名2:b)
selecta.a,a.b,a.c,b.c,b.d,b.ffromaLEFTOUTJOINbONa.a=b.c
說(shuō)明:日程安排提前五分鐘提醒
select*from日程安排wheredatediff('minute',f開(kāi)始時(shí)間,getdate())>5
說(shuō)明:兩張關(guān)聯(lián)表,刪除主表中已經(jīng)在副表中沒(méi)有的信息
deletefrominfowherenotexists(select*frominfobzwhereinfo.infid=infobz.infid)
說(shuō)明:-- SQL: SELECTA.NUM,A.NAME,B.UPD_DATE,B.PREV_UPD_DATE FROMTABLE1, (SELECTX.NUM,X.UPD_DATE,Y.UPD_DATEPREV_UPD_DATE FROM(SELECTNUM,UPD_DATE,INBOUND_QTY,STOCK_ONHAND FROMTABLE2 WHERETO_CHAR(UPD_DATE,'YYYY/MM')=TO_CHAR(SYSDATE,'YYYY/MM'))X, (SELECTNUM,UPD_DATE,STOCK_ONHAND FROMTABLE2 WHERETO_CHAR(UPD_DATE,'YYYY/MM')= TO_CHAR(TO_DATE(TO_CHAR(SYSDATE,'YYYY/MM')||'/01','YYYY/MM/DD')-1,'YYYY/MM'))Y, WHEREX.NUM=Y.NUM(+) ANDX.INBOUND_QTY+NVL(Y.STOCK_ONHAND,0)<>X.STOCK_ONHAND)B WHEREA.NUM=B.NUM
說(shuō)明:--
select*fromstudentinfowherenotexists(select*fromstudentwhere
studentinfo.id=student.id)and系名稱(chēng)='"&strdepartmentname&"'and專(zhuān)業(yè)名稱(chēng)
='"&strprofessionname&"'orderby性別,生源地,高考總成績(jī)
從數(shù)據(jù)庫(kù)中去一年的各單位電話費(fèi)統(tǒng)計(jì)(電話費(fèi)定額賀電化肥清單兩個(gè)表來(lái)源) SELECTa.userper,a.tel,a.standfee,TO_CHAR(a.telfeedate,'yyyy')AStelyear, SUM(decode(TO_CHAR(a.telfeedate,'mm'),'01',a.factration))ASJAN, SUM(decode(TO_CHAR(a.telfeedate,'mm'),'02',a.factration))ASFRI, SUM(decode(TO_CHAR(a.telfeedate,'mm'),'03',a.factration))ASMAR, SUM(decode(TO_CHAR(a.telfeedate,'mm'),'04',a.factration))ASAPR, SUM(decode(TO_CHAR(a.telfeedate,'mm'),'05',a.factration))ASMAY, SUM(decode(TO_CHAR(a.telfeedate,'mm'),'06',a.factration))ASJUE, SUM(decode(TO_CHAR(a.telfeedate,'mm'),'07',a.factration))ASJUL, SUM(decode(TO_CHAR(a.telfeedate,'mm'),'08',a.factration))ASAGU, SUM(decode(TO_CHAR(a.telfeedate,'mm'),'09',a.factration))ASSEP, SUM(decode(TO_CHAR(a.telfeedate,'mm'),'10',a.factration))ASOCT, SUM(decode(TO_CHAR(a.telfeedate,'mm'),'11',a.factration))ASNOV, SUM(decode(TO_CHAR(a.telfeedate,'mm'),'12',a.factration))ASDEC FROM(SELECTa.userper,a.tel,a.standfee,b.telfeedate,b.factration FROMTELFEESTANDa,TELFEEb WHEREa.tel=b.telfax)a GROUPBYa.userper,a.tel,a.standfee,TO_CHAR(a.telfeedate,'yyyy')
說(shuō)明:四表聯(lián)查問(wèn)題
select*fromaleftinnerjoinbona.a=b.brightinnerjoincona.a=c.cinnerjoindon
a.a=d.dwhere.....
說(shuō)明:得到表中最小的未使用的ID號(hào)
SELECT(CASEWHENEXISTS(SELECT*FROMHandlebWHEREb.HandleID=1)THENMIN(HandleID)+1
ELSE1END)asHandleIDFROMHandleWHERENOTHandleIDIN(SELECTa.HandleID-1FROM
Handlea)
一個(gè)SQL語(yǔ)句的問(wèn)題:行列轉(zhuǎn)換
select*fromv_temp
上面的視圖結(jié)果如下:
user_namerole_name
-------------------------
系統(tǒng)管理員管理員
feng管理員
feng一般用戶(hù)
test一般用戶(hù)
想把結(jié)果變成這樣:
user_namerole_name
---------------------------
系統(tǒng)管理員管理員
feng管理員,一般用戶(hù)
test一般用戶(hù)
===================
createtablea_test(namevarchar(20),role2varchar(20))
insertintoa_testvalues('李','管理員')
insertintoa_testvalues('張','管理員')
insertintoa_testvalues('張','一般用戶(hù)')
insertintoa_testvalues('常','一般用戶(hù)') createfunctionjoin_str(@contentvarchar(100))
returnsvarchar(2000)
as
begin
declare@strvarchar(2000)
set@str=''
select@str=@str+','+rtrim(role2)froma_testwhere[name]=@content
select@str=right(@str,len(@str)-1)
return@str
end
go --調(diào)用:
select[name],dbo.join_str([name])role2froma_testgroupby[name] --selectdistinctname,dbo.uf_test(name)froma_test
快速比較結(jié)構(gòu)相同的兩表
結(jié)構(gòu)相同的兩表,一表有記錄3萬(wàn)條左右,一表有記錄2萬(wàn)條左右,我怎樣快速查找兩表的不同記錄?
============================
給你一個(gè)測(cè)試方法,從northwind中的orders表取數(shù)據(jù)。
select*inton1fromorders
select*inton2fromorders select*fromn1
select*fromn2 --添加主鍵,然后修改n1中若干字段的若干條
altertablen1addconstraintpk_n1_idprimarykey(OrderID)
altertablen2addconstraintpk_n2_idprimarykey(OrderID) selectOrderIDfrom(select*fromn1unionselect*fromn2)agroupbyOrderIDhaving
count(*)>1 應(yīng)該可以,而且將不同的記錄的ID顯示出來(lái)。
下面的適用于雙方記錄一樣的情況, select*fromn1whereorderidin(selectOrderIDfrom(select*fromn1unionselect*from
n2)agroupbyOrderIDhavingcount(*)>1)
至于雙方互不存在的記錄是比較好處理的
--刪除n1,n2中若干條記錄
deletefromn1whereorderIDin('10728','10730')
deletefromn2whereorderIDin('11000','11001') --*************************************************************
--雙方都有該記錄卻不完全相同
select*fromn1whereorderidin(selectOrderIDfrom(select*fromn1unionselect*from
n2)agroupbyOrderIDhavingcount(*)>1)
union
--n2中存在但在n1中不存的在10728,10730
select*fromn1whereOrderIDnotin(selectOrderIDfromn2)
union
--n1中存在但在n2中不存的在11000,11001
select*fromn2whereOrderIDnotin(selectOrderIDfromn1)
四種方法取表里n到m條紀(jì)錄: 1.
selecttopm*into臨時(shí)表(或表變量)fromtablenameorderbycolumnname--將topm筆插入
setrowcountn
select*from表變量orderbycolumnnamedesc
2.
selecttopn*from(selecttopm*fromtablenameorderbycolumnname)aorderby
columnnamedesc
3.如果tablename里沒(méi)有其他identity列,那么:
selectidentity(int)id0,*into#tempfromtablename 取n到m條的語(yǔ)句為:
select*from#tempwhereid0>=nandid0<=m 如果你在執(zhí)行selectidentity(int)id0,*into#tempfromtablename這條語(yǔ)句的時(shí)候報(bào)錯(cuò),那是因?yàn)?
你的DB中間的selectinto/bulkcopy屬性沒(méi)有打開(kāi)要先執(zhí)行:
execsp_dboption你的DB名字,'selectinto/bulkcopy',true
4.如果表里有identity屬性,那么簡(jiǎn)單:
select*fromtablenamewhereidentitycolbetweennandm
如何刪除一個(gè)表中重復(fù)的記錄?
createtablea_dist(idint,namevarchar(20)) insertintoa_distvalues(1,'abc')
insertintoa_distvalues(1,'abc')
insertintoa_distvalues(1,'abc')
insertintoa_distvalues(1,'abc') execup_distinct'a_dist','id' select*froma_dist createprocedureup_distinct(@t_namevarchar(30),@f_keyvarchar(30))
--f_key表示是分組字段﹐即主鍵字段
as
begin
declare@maxinteger,@idvarchar(30),@sqlvarchar(7999),@typeinteger
select@sql='declarecur_rowscursorforselect'+@f_key+',count(*)from'+@t_name+'
groupby'+@f_key+'havingcount(*)>1'
exec(@sql)
opencur_rows
fetchcur_rowsinto@id,@max
while@@fetch_status=0
begin
select@max=@max-1
setrowcount@max
select@type=xtypefromsyscolumnswhereid=object_id(@t_name)andname=@f_key
if@type=56
select@sql='deletefrom'+@t_name+'where'+@f_key+'='+@id
if@type=167
select@sql='deletefrom'+@t_name+'where'+@f_key+'='+''''+@id+''''
exec(@sql)
fetchcur_rowsinto@id,@max
end
closecur_rows
deallocatecur_rows
setrowcount0
end select*fromsystypes
select*fromsyscolumnswhereid=object_id('a_dist')
查詢(xún)數(shù)據(jù)的最大排序問(wèn)題(只能用一條語(yǔ)句寫(xiě))
CREATETABLEhard(quchar(11),cochar(11),jenumeric(3,0)) insertintohardvalues('A','1',3)
insertintohardvalues('A','2',4)
insertintohardvalues('A','4',2)
insertintohardvalues('A','6',9)
insertintohardvalues('B','1',4)
insertintohardvalues('B','2',5)
insertintohardvalues('B','3',6)
insertintohardvalues('C','3',4)
insertintohardvalues('C','6',7)
insertintohardvalues('C','2',3)
要求查詢(xún)出來(lái)的結(jié)果如下: qucoje
---------------------------
A69
A24
B36
B25
C67
C34
就是要按qu分組,每組中取je最大的前2位??!
而且只能用一句sql語(yǔ)句?。?!
select*fromhardawherejein(selecttop2jefromhardbwherea.qu=b.quorderbyje)
求刪除重復(fù)記錄的sql語(yǔ)句?
怎樣把具有相同字段的紀(jì)錄刪除,只留下一條。
例如,表test里有id,name字段
如果有name相同的記錄只留下一條,其余的刪除。
name的內(nèi)容不定,相同的記錄數(shù)不定。
有沒(méi)有這樣的sql語(yǔ)句?
==============================
A:一個(gè)完整的解決方案: 將重復(fù)的記錄記入temp1表:
select[標(biāo)志字段id],count(*)intotemp1from[表名]
groupby[標(biāo)志字段id]
havingcount(*)>1 2、將不重復(fù)的記錄記入temp1表:
inserttemp1select[標(biāo)志字段id],count(*)from[表名]groupby[標(biāo)志字段id]havingcount(*)
=1 3、作一個(gè)包含所有不重復(fù)記錄的表:
select*intotemp2from[表名]where標(biāo)志字段idin(select標(biāo)志字段idfromtemp1) 4、刪除重復(fù)表:
delete[表名] 5、恢復(fù)表:
insert[表名]select*fromtemp2
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