Izitatimende SQL Eziyisisekelo

SQL ejwayelekile wamukelwa ngonyaka 1992 futhi esasetshenziswa nanamuhla. Lokho usebé lokuma eziningi ngabaphathi semininingwane izinhlelo. Yiqiniso, abanye abakhiqizi ukusebenzisa ukuhumusha okungokwakhe standard. Kodwa yiluphi uhlelo, kusenabantu yezingxenye esemqoka - izitatimende SQL.

isingeniso

Ukusebenzisa izitatimende SQL database kwenzeka amagugu ukuphathwa kumathebula sokulungiselela yabo ye ukuhlaziya olunye futhi ukubonisa. Ziyakwazi iqoqo angukhiye, lapho uhlelo uyazi ukuthi wenzeni idatha.

Chaza izigaba eziningana izitatimende SQL:

• definition yemininingo egciniwe izinto;
• ukuxhaphaza amagugu;
• Ukuvikelwa nokuphathwa;
• Iseshini nemingcele;
• Ulwazi mayelana isizinda;
• SQL static;
• SQL ashukumisayo.

izitatimende SQL yedatha zokukhwabanisa

Lesi sigaba sihlanganisa angukhiye ngawo ungakwazi ukulawula ukubekwa yamanani database.

FAKA. Ifaka ilandelana ithebula ekhona. Ingasetshenziselwa njengoba inani elilodwa noma amaningi, kuchazwe isimo esithile. Ngokwesibonelo:

FAKA EKUDLENI

igama ithebula (ikholomu 1 igama, igama kukholamu 2)

IZIMO (inani 1 Inani 2).

Ukusebenzisa opharetha SQL sitatimende FAKA amanani amaningi, sebenzisa i-syntax ezilandelayo:

FAKA EKUDLENI

igama 1 ithebula (ikholomu 1, igama ikholomu 2)

KHETHA igama ikholomu 1, ikholomu 2

KUSUKELA igama lethebula 2

LAPHO igama 2.imya yethebula 1> 2

Lokhu nombuzo ukhetha yonke idatha ku Table 2, okuyinto mkhulu kunezinhliziyo 2 1 ikholomu futhi uwanamathisela kuqala.

UPDATE. Njengoba leli gama lisikisela, kwakhishwa lesi simemezelo ilungisa idatha nombuzo SQL e ithebula ekhona njalo ezithile.

Ngokwesibonelo:

UPDATE igama lethebula 1

igama ISETHI ikholomu = 2 "Basil"

LAPHO ithebula igama 1.imya ikholomu 1 = 1

Lesi sakhiwo yokugcwalisa ukubaluleka Basil yonke imigqa ahlangabezana inombolo 1 kukholamu yekucala.

SUSA. Isula idatha kusuka etafuleni. Ungakwazi ucacise noma yimuphi umbandela noma ukususa yonke imigqa.

SUSA KUSUKELA igama lethebula

LAPHO igama tablitsy.imya ikholomu 1 = 1

Umbuzo ngenhla kuzosusa yonke idatha kusuka database ne nenani elilodwa kukholomu yokuqala. Nakhu ukuthi ungakwazi ukusula wonke ithebula:

SUSA KUSUKELA igama lethebula.

Okulandelayo kuyadingeka ukuze ikhulume isitatimende KHETHA. Ungomunye abaluleke kakhulu, ngakho kuyodingeka ukuba achithe isahluko ehlukene.

isitatimende KHETHA

Injongo eyinhloko KHETHA - Ukukhetha idatha ngokuvumelana nezimo ezithile. Umphumela womsebenzi wakhe uhlale ithebula elisha nge idatha ekhethiwe. MS-opharetha SQL KHETHA ingasetshenziswa isisindo izicelo ezahlukene. Ngakho-ke, kanye-ke, ungase ucabangele ezinye angukhiye ahlobene.

Ukukhetha konke uphawu idatha "*" lisetshenziswa kusukela itafula ethile.

KHETHA *

KUSUKELA igama lethebula 1

Waba yini umphumela walesi nombuzo kuyoba ikhophi esiqondile etafuleni 1.

Futhi nangu alandiwe ngu LAPHO isimo esenza losusa kuThebula 1, wonke amanani olukhulu kunalolu 2 kwikholomu 1.

KHETHA *

KUSUKELA igama lethebula 1

LAPHO igama 1.imya yethebula 1> 2

Ungase futhi ucacise okukhethiwe ukuthi kuphela amakholomu ezithile ezidingekayo.

KHETHA igama lethebula 1.imya ikholomu 1

KUSUKELA igama lethebula 1

Waba yini umphumela walesi nombuzo bonke imigqa amanani kukhalamu 1. Ukusebenzisa MS SQL opharetha ungakha ithebula ayo, ngokuhamba esikhundleni, kubalwa kanye abambele amagugu ethile.

KHETHA

igama lethebula 1.imya ikholomu 1

igama lethebula 1.imya ikholomu 2

igama lethebula 1.imya ikholomu 3

«=» NJENGOBA EQ

igama lethebula 1.imya ikholomu 2 kwegama etafuleni * 1.imya ikholomu 3 NJENGOBA Summa

KUSUKELA igama lethebula 1

Lokhu nombuzo ezibonakala eziyinkimbinkimbi fetches zonke amagugu Ithebula 1, bese kudala ikholomu entsha futhi EQ Summa. Okokuqala ingena uphawu "+", okwesibili yedatha komkhiqizo 2 futhi 3. Lo mphumela kungenziwa imelelwa itafula, ukuze uqonde ukuthi isebenza kanjani:

ikholomu 1	ikholomu 2	ikholomu 3	EQ	Summa
Igama lomkhiqizo 1	10	50	+	500
Igama lomkhiqizo 2	15	100	+	1500

Uma usebenzisa isitatimende KHETHA, ungakwazi ngokushesha ukuchitha iyala idatha ngenxa yananoma yiziphi izizathu. Isebenzisa igama elithi ORDER BY.

KHETHA

igama lethebula 1.imya ikholomu 1

igama lethebula 1.imya ikholomu 2

igama lethebula 1.imya ikholomu 3

KUSUKELA igama lethebula 1

ORDER BY igama ikholomu 2

Ithebula okuholela izobukeka kanje:

ikholomu 1	ikholomu 2	ikholomu 3
1	1	54
3	2	12
7	3	100
2	5	1

Lokho, wonke imigqa isifakiwe ngendlela yokuthi kukholamu 2 amagugu abangu sinyuka.

Idatha ayathola lolutfolakala kumathebula amaningi. Ngokucaca, kuzomele uqale ukucabanga ukuthi banayo ezimbili, abanye basesimweni database:

Ithebula "Abasebenzi"

inombolo	igama	nesibongo
1	Vasya	Vasin
2	Petya	Petin

Ithebula "Iholo"

inombolo	izinga	udumo
1	1	10000
2	0.5	3500

Manje kudingeka, ezifana ngokuxhumanisa Ngasengibamba izibhebhe zombili ukuze uthole ezindinganisweni ezifanayo. Ukusebenzisa SQL eziyisisekelo izitatimende ke kungenziwa kanje:

KHETHA

Sotrudniki.Nomer

Sotrudniki.Imya

Zarplata.Stavka

Zarplata.Nachisleno

KUSUKELA Abasebenzi Salary

LAPHO Sotrudniki.Nomer = Zarplata.Nomer

Kukhona ilandwe amatafula amabili ezahlukene amagugu, behlanganiswe inombolo. Umphumela elandelayo idatha:

inombolo	igama	izinga	udumo
1	Vasya	1	10000
2	Petya	0.5	3500

Kancane okwengeziwe KHETHA. Ukusebenzisa imisebenzi aggregate

Omunye eziyisisekelo izitatimende SQL KHETHA angakhiqiza ezinye izibalo isampuli. Ukuze wenze lokhu, usebenzisa imisebenzi ethile kanye namafomula.

Ngokwesibonelo, ukuze uthole inani amarekhodi etafuleni "Abasebenzi", udinga ukusebenzisa nombuzo:

COUNT KHETHA (*) NJENGOBA N

KUSUKELA Abasebenzi

Umphumela walokhu uyoba itafula nge ikholomu eyodwa nokubaluleka.

N

2

umsebenzi ingasetshenziswa imibuzo ukuthi ukubala isamba, esiphezulu kanye namagugu esincane, futhi ngokwesilinganiso. Ukuze wenze lokhu, angukhiye asetshenziselwa SUM, MAX,-MIN, AVG.

Ngokwesibonelo, kubalulekile ukuba ubambe isampula "Iholo" etafuleni eyaziwa kakade:

inombolo	izinga	udumo
1	1	10000
2	0.5	3500

Ungafaka isicelo leso sicelo futhi sibone ukuthi kwenzekani:

KHETHA

INANI (Zarplata.Nachisleno) NJENGOBA Summa

UMKHAWULO (Zarplata.Nachisleno) NJENGOBA-MAX

OKUNCANE (Zarplata.Nachisleno) NJENGOBA-MIN

AVG (Zarplata.Nachisleno) NJENGOBA SRED

KUSUKELA Salary

Ithebula sokugcina kuyoba kanje:

Summa	-MAX	-MIN	SRED
13500	10000	3500	6750

Yileyondlela, ungakhetha kusukela database amagugu ezifanele epheshaneni ukwenza ekubalweni imisebenzi ehlukahlukene.

Union, ezimpambanweni zomgwaqo futhi umehluko

Hlanganisa imibuzo amaningi SQL

KHETHA Sotrudniki.Imya

KUSUKELA Abasebenzi

LAPHO Sotrudniki.Nomer = 1

INYUNYANA

KHETHA Sotrudniki.Imya

KUSUKELA Abasebenzi Salary

LAPHO Zarplata.Nomer = 1

Kumele kukhunjulwe ukuthi kuleli thebula inhlangano kumelwe buvumelane. Okungukuthi, abe namaswidi alingana lamakholomu.

I-syntax isitatimende KHETHA kanye nenqubo ukuze kusebenziswe

Into yokuqala KHETHA inquma indawo kusuka okuyinto kuzothatha idatha. Ukuze wenze lokhu, sebenzisa elisemqoka FROM. Uma kungacacisiwe, lokho ukukhetha.

Ungabese ukwethula isitatimende SQL LAPHO. Ngosizo KHETHA ligijima umugqa etafuleni ngalinye futhi ihlola idatha kuhambisana nesimo.

Uma sinephutha GROUP BY, khona-ke Ukubuthelela amagugu yalezi nemingcele.

Opharetha ukuqhathanisa idatha

Sinenkosi izinhlobo eziningana. Ngo SQL ukuqhathanisa opharetha bangahlola izinhlobo ezahlukene amagugu.

• "=". Lisho, njengoba ungase ukuqagela, ukulingana zezinkulumo ezimbili. Isibonelo, isivele isetshenzisiwe sibonile ezibonelweni ezingenhla - LAPHO Zarplata.Nomer = 1.

• ">". Greater-uphawu. Uma ukubaluleka ohlangothini lwesobunxele le nkulumo mkhulu ke TRUE okunengqondo ebuyiselwa futhi isimo uhlangana.

• "<". Ngaphansi kuka uphawu. Reverse opharetha odlule.

• Izimpawu "<=" futhi "> =". Uhluka opharetha elula kakhudlwana futhi kancane ukuthi nge operands alinganayo isimo nakho kuyiqiniso.

• "<>". Angikhathali. Isimo kubhekwa TRUE, uma we- eyodwa kuphela ayilingani omunye. Anakho eyodwa ngaphezulu incazelo - "! =".

NJENGO

Humusha lo elisemqoka kungaba ngokuthi "efanayo." NJENGO opharetha SQL isetshenziswa cishe ku isimiso esifanayo - ugijima umbuzo kusuka isifanekiso. Okungukuthi, ikuvumela ukuba sandise idatha isampula database usebenzisa izengezo ezivamile.

Ngokwesibonelo, linikeza lo msebenzi: kusukela phansi "abasebenzi" eyaziwa kakade ukuze uthole bonke abantu ogama lakhe iphela "Mina". Khona-ke isicelo kungenziwa yakhiwe ngendlela elandelayo:

KHETHA *

KUSUKELA Abasebenzi

LAPHO Igama NJENGO `% I`ll

Amaphesenti uphawu kuleli cala kusho imaskhi, okungukuthi, noma yimuphi uhlamvu, futhi isibalo sawo. Futhi kule ncwadi, "Mina» SQL enquma ukuthi uhlamvu lokugcina kube njalo.

Case

Lokhu Server isitatimende SQL kuyinto ukuqaliswa ukukhetha okuningi. It sifana Isitatimende sokushintsha kuzilimi eziningi zokuhlela. Case sitatimende SQL wenza isenzo ezimeni eziningana.

Ngokwesibonelo, ukhetha itafula "iholo" esiphezulu kanye namagugu ubuncane.

inombolo	izinga	udumo
1	1	10000
2	0.5	3500

Khona-ke isicelo kungenziwa yakhiwe ngendlela elandelayo:

KHETHA *

KUSUKELA Salary

LAPHO UMA UMA KHETHA UMKHAWULO (Uzikhokhele) KUDALA Ubuningi

UMA KHETHA OKUNCANE (Uzikhokhele) KUDALA Ubuncane

UKUPHELA yi

ku "Uzikhokhele" ikholomu kulo mongo, uhlelo ibheka seqiwe bese ubuncane. Khona-ke, usebenzisa UKUPHELA ensimini wadala "Imininingwane", okuzokwenza kube ungene ku "esiphezulu" noma "ubuncane" kuye ngokuthi umphumela isimo.

By endleleni, ngo-SQL kukhona ifomu compact ngaphezulu Case - coalesce.

idatha definition

Lo mbono ikuvumela ukuba afeze ezihlukahlukene amatafula ekushintsheni - dala, susa, shintsha, futhi sisebenze izinkomba.

Eyokuqala, okuyinto kuyafaneleka ukucabangela - DALA ITHEBULA. Wenza lutho okunye ukwedlula ukudala itafula. Uma nje uthayipha DALA nombuzo ITHEBULA, ayikho into ezokwenzeka, ngoba udinga ukucacisa nemingcele eziningana.

Ngokwesibonelo, ukwakha etafuleni ajwayelekile "Abasebenzi" ufuna ukusebenzisa umyalo:

DALA ITHEBULA Abasebenzi

(Inombolo kamazisi (10) HHAYI null

Igama varchar (50) HHAYI null

Isibongo varchar (50) HHAYI null)

Kulesi isicelo, kubakaki ngokushesha kuchazwa amagama ensimini nezinhlobo zazo, kanye noma ngabe kungaba null.

Drop ITHEBULA

Ukwenza umsebenzi elula - kokukhipha itafula wathi. It has inketho ezengeziwe UMA LIKHONA. It ubamba nephutha ngesikhathi kususwa, uma etafuleni edingekayo ayikho. Isibonelo ukusetshenziswa:

Drop ITHEBULA Abasebenzi UMA LIKHONA.

DALA INDEX kwangu

Ngo SQL, kukhona simiso indices, okuvumela ukufinyelela ngokushesha kwi-data. Ngokuvamile, kuba isixhumanisi kukhomba ikholomu ethile. Dala i-index kungaba isicelo elula:

DALA INDEX kwangu nazvanie_indeksa

KU nazvanie_tablitsy (nazvanie_stolbtsa)

Sebenzisa lesi sitatimende-T SQL, Oracle, PL SQL neminye ukutolika ubuchwepheshe.

Alter ITHEBULA

opharetha kakhulu ukusebenza nge izinketho eziningi. Ngokuvamile, ushintsho ukhiqiza incazelo isakhiwo namathebula Kwabiwa. Operator isetshenziswa ku-Oracle SQL, Postgres, nabanye abaningi.

Izikhombo manje banikelwe ongakhetha ahlukahlukene usebenzisa ukushintsha ITHEBULA.

• ADD. Kwenta ukwengeza ikholomu itafula. Syntax kuye lokhu: ukushintsha ITHEBULA ADD nazvanie_tablitsy nazvanie_stolbtsa tip_hranimyh_dannyh. Ungaba ipharamitha IF NOT LIKHONA, okuyinto ukucindezela nephutha uma ikholomu isivele idale;

• Drop. Ikhipha ikholomu. UMA LIKHONA nayo kuphelile, okuyinto ezokwenzela nephutha ethi akekho kukholamu oceliwe;

• Ukuphenduka. Isetshenziswa ukuqamba kabusha igama enkambini ecacisiwe. Isibonelo ukusetshenziswa: ukushintsha ITHEBULA Ukuphenduka nazvanie_tablitsy OldName NEW_NAME;

• Guqula. Lo myalo izoshintsha uhlobo ikholomu ethile futhi izimfanelo ezengeziwe. Futhi isetshenziswa kanje: ukushintsha ITHEBULA guqula nazvanie_tablitsy nazvanie_stolbtsa datatype izingxenye;

DALA BUKA

Ngo SQL, kukhona into enjalo njengoba umbono. Kafushane, kuba uhlobo ithebula virtual idatha. Kumiswa It is ngenxa isampuli usebenzisa ulimi SQL KHETHA isitatimende. Ukubukwa ongasivimbela database uwafihle, ukuthatha indawo yangempela amagama ikholomu.

Inqubo ekudaleni kwenzeka ngo umbuzo olula:

DALA BUKA buka igama NJENGOBA KHETHA KUSUKELA * igama lethebula

Isampula kungathatha indawo baliklasi lonkhe semininingwane wonkana, futhi usesimweni ezithile.

Kancane mayelana nezici

Ngo SQL imibuzo ngokuvamile zisebenzisa imisebenzi ehlukene esakhelwe ezikuvumela uxhumana idatha futhi ukuguqula kwabo on the fly. It kuyafaneleka ukucabangela kwabo, njengoba nje kuvamile namanje iyingxenye ebalulekile ulimi ehlelekile.

• COUNT. Ukhicita ngokubala imigqa noma okufakiwe itafula ethile. Njengoba inketho, ungacacisa igama ikholomu, bese idatha uyothathwa kuye. KHETHA COUNT * KUSUKELA Abasebenzi;

• AVG. Lesi sici sisebenza kuphela amakholomu ngedatha ezinombolo. yi Its ukuzimisela kusho izibalo wonke amanani;

• MIN no-MAX. Lezi imisebenzi Kuye asetshenziswe kulesi sihloko. Abakuchaza esiphezulu kanye namagugu ubuncane ikholomu wathi;

• SUM. Kulula - umsebenzi sinquma isamba yamanani ikholomu. Isetshenziselwa kuphela ezinombolo uhlobo idatha. Ukungeza ipharamitha isicelo abahlukene, niyozenezelelwa kuphela ahlukile;

• INDILINGA. Umsebenzi ukuqoqa idesimali izinombolo wamaqhuzu. I-syntax esetshenziswa igama ikholomu kanye inombolo yezindawo zedesimali;

• LEN. A umsebenzi esilula ukuthi sinquma ubude ikholomu. Umphumela walokhu uyoba ithebula elisha okubonisa Inani lezinhlamvu;

• MANJE. Lokhu elisemqoka isetshenziselwa ukubala idethi nesikhathi samanje.

opharetha ezengeziwe

Izibonelo eziningi izitatimende SQL angukhiye ukuthi ukwenza imisebenzi emincane, kodwa nokho kakhulu lula isampula noma umsebenzi egciniwe.

• NJENGOBA. Isetshenziselwa uma ufuna ukuba zibukeke ahlele yi sabele igama elicacisiwe ukuthola itafula.

• PHAKATHI. Ithuluzi Ukugunda kakhulu izibonelo zalokho. Ikhombisa ububanzi bamanani, kuhlanganise nesidingo ukuthola idatha. Umngcele we-okokufaka uthola kusuka futhi ibanga inombolo isetshenziswa.

• HHAYI. I-opharetha unika okuphambene okuvela kuyo le nkulumo.

• QUNTA. Isusa idatha kusuka wathi base ingxenye. Ihlukile kuleyo opharetha ukuthi alulame idatha emva ukusetshenziswa kwalo akunakwenzeka. Kuyaphawuleka ukuthi ukuqaliswa elisemqoka inikezwe e SQL ezahlukene kungaba ukutolika ezahlukene. Ngakho-ke ngaphambi kokuzama ukusebenzisa QUNTA, kangcono ulwazi ngemuva.

• LIMIT. Imisa inani okukhipha imigqa. I engavamile we-opharetha ukuthi njalo elise ekupheleni. Kuthatha eyodwa amandla futhi omunye ipharamitha ozikhethela. Eyokuqala kubonisa kanjani imigqa eminingi ngedatha akhethiwe ukukhombisa. Futhi uma yesibili, bese opharetha usebenza kokubili ububanzi bamanani.

• INYUNYANA. Kakhulu opharetha kusebenziseka kalula sihlanganise imibuzo amaningi. Uvele usezibophezele wahlangana phakathi izibonelo zalokhu kulesi sihloko. Ungabonisa imigqa lolutfolakala kumathebula amaningi, UNION hlanganisa them ukusetshenziswa elula kakhudlwana. Syntax kuye lokhu: KHETHA COLUMN_NAME KUSUKELA ithebula UNION KHETHA KUSUKELA ithebula imya_drugogo_stolbtsa imya_drugoy. Imiphumela iba yinhlanganisela yokukhandleka ithebula isifinyezo izimfuno onobunye.

• KEY LWEBELE. Elihunyushwa ngokuthi "ukhiye oyihloko." Empeleni, ukuthi amagama anjalo isetshenziswa inkomba izinto. He is id ehlukile kumugqa. Isetshenziselwa, njengoba umthetho, uma udala itafula ukuze ukhombise kwensimu sizoqukatha ke.

• OKUZENZAKALELAYO. Njengoba nje u-opharetha langaphambilini, elisetshenziswa ukuqaliswa udala nombuzo. Kuchaza ukubaluleka okuzenzakalelayo, oyogcwala emkhakheni lapho edala.

Amathiphu ambalwa ukuthuthukisa nesigcawu ukusebenza SQL

1. Null. Beginners hhayi nje program ekulungiseleleni izicelo bavame ukukhohlwa ukutholakala null amagugu obakhathalelayo. Ngenxa yalokho, ikhodi yephutha aqala, okuyinto okunzima ukulandelela enqubeni kungasebenzi. Ngakho-ke, uma udala itafula, noma recalculated isampula amagugu kudingeka ukuba sime, sicabange, nokuthi null nesenzakalo is kunakwe endaweni nombuzo.

2. Memory. Kuleli phephandaba esasiboniswa eziningi imisebenzi, ongenza imisebenzi ethile. Ngo ukuthuthukiswa igobolondo ukusebenza database, ungakwazi "zinkulu" ukubala wokuboniswa elula uhlelo egciniwe. Kwezinye izimo, lokhu kunikeza umfutho okuphawulekayo ukusebenza.

3. Imikhawulo. Uma ufuna ukuthola kusuka database nezinkulungwane imigqa emibili kuphela, kubalulekile ukusebenzisa opharetha ezifana LIMIT noma TOP. Asikho isidingo ukuthola idatha esebenzisa igobolondo zokuthuthukiswa kolimi.

4. Xhuma. Phezu kokuthola idatha kusuka ematafuleni amaningana, program eziningi ziqala ukunciphisa ndawonye invilophu inkumbulo kusho. Kodwa kungani? Phela, ungenza isicelo lapho konke kuzakuba khona. Awunayo ukubhala ikhodi kanye uzibekele inkumbulo ezengeziwe ohlelweni.

5. Ukuhlunga. Uma kungenzeka ukusebenzisa isiqondiso isicelo, okungukuthi, amabutho DBMS, kubalulekile ukuyisebenzisa. Lokhu kuyokwenza ugcine kakhulu ngezinsiza lapho uhlelo noma isevisi.

6. izicelo eziningi. Uma une ukufaka eziningi amarekhodi ngokulandelana ke nokwenza kufanele ucabange idatha iphakethe ifakwe isicelo sayo esisodwa. Lokhu kuzophinde ukwandisa ukusebenza lonke uhlelo.

7. ukubekwa ngokucophelela idatha. Ngaphambi ezilandelwayo isakhiwo isizinda kudingeka ucabange indlela futhi kungakhathaliseki ukuthi isibalo esingangaleso amathebula namasimu kunesidingo. Mhlawumbe kukhona indlela ukuhlanganisa kubo, noma siyeke phansi abanye. Isikhathi esining impela, program zisebenzisa isamba ngokweqile idatha ndawo futhi akazange asebenzise.

8. Izinhlobo. Ukuze ulondoloze isikhala nezisetshenziswa kudingeka sibe nozwelo izinhlobo zedatha esetshenziswa. Uma ungakwazi ngokunenzuzo kancane "ezisinda" kangaka uhlobo inkumbulo, kufanele sisebenzise igama lakhe. Ngokwesibonelo, uma lowo eyaziwa kule nsimu yinani lenombolo ngeke idlule 255, kungani ukusetshenziswa 4-Byte INT, uma kukhona TINYINT 1 ibhayithi.

isiphetho

Ekuphetheni, kufanele kuphawulwe ukuthi ulimi wakhiwe imibuzo SQL manje selisetshenziswa cishe yonke indawo - amawebhusayithi, amasevisi wewebhu, isofthiwe ideskithophu, kwizinhlelo zokusebenza zeselula. Ngakho-ke, SQL ulwazi kuzosiza yonke imikhakha yentuthuko.

Nokho, ukuguqulwa bomdabu ulimi standard ngezinye izikhathi ihluke nomunye. Ngokwesibonelo, PL SQL opharetha angase abe-syntax ehlukile kunaleyo e SQL Server. Ngakho ngaphambi kokuba uqale ekuthuthukiseni nalesi ezobuchwepheshe, kubalulekile ukuba bajwayelane ke ngeziqondiso.

Esikhathini nozakwabo esizayo, okungase adlula ukusebenza SQL kanye nokusebenza, akunakwenzeka ukuba avele, ngakho kulesi sigaba kuyinto ngempela niche esithembisayo iyiphi uMklami.