Imibuzo ikhupha amandla eenkcukacha zakho
Umbuzo wesiseko uchonga idatha esuka kwisiseko sedatha kwaye uyifake kwifom efundekayo. Umbuzo kufuneka ubhalwe phantsi ngolwimi olufunwa lulwazi-ngokuqhelekileyo, olo lwimi luyiSQL .
Umzekelo, xa ufuna idatha ukusuka kwiziko ledatha, usebenzisa umbuzo ukucela ulwazi oluthile olufunayo. Mhlawumbi unetafile yomqeshwa, kwaye ufuna ukulandelela amanqaku okusebenza okuthengisa. Unokuzibuza umgca wakho wesiseko kumqeshwa obhale ixabiso eliphezulu kwixesha elithile.
Isitatimende seSQL SELECT
Umbuzo wesiseko kufuneka ulandele ifomathi yesicelo efunwa yi database. Ifomathi eqhelekileyo yiLwimi oluCwangcisiweyo loPhando lwemibuzo (SQL) ifomathi yombuzo oqhelekileyo osetyenziswe ezininzi iinkqubo zolawulo lweenkcukacha. I-SQL yilwimi elinamandla elinemibuzo ephakamileyo.
I-SQL isebenzisa isitethi SELECT ukukhetha idatha ethile.
Cinga ngomzekelo esekelwe kwi-database yaseNorthwind esoloko ihamba kunye nemikhiqizo yedatha njengesifundo.
Nantsi ingqungquthela evela kwitheyibhile yabaSebenzi beDatabase:
| EmployeeID | Ifani | Igama lokuqala | Isihloko | Idilesi | Sixeko | Ummandla | |
|---|---|---|---|---|---|---|---|
| 1 | Davolio | UNancy | Umntu omele intengiso | 507 - 20 Ave. E. | Seattle | WA | |
| 2 | Epheleleyo | Andrew |
| 908 W. Capital Way | Tacoma | WA | |
| 3 | Leverling | UJanet | Umntu omele intengiso | 722 Moss Bay Blvd. | Kirkland | WA |
Ukubuyisela igama lomqeshwa kunye nesihloko kwisiseko sedata, ISICELO sokukhetha sizakujonga into enje:
UKUKHETHA I-FirstName, LastName, Isihloko kuBasebenzi;
Kuya kubuya:
| Igama lokuqala | Ifani | Isihloko |
|---|---|---|
| UNancy | Davolio | Umntu omele intengiso |
| Andrew | Epheleleyo | I-Vice-President, Sales |
| UJanet | Leverling | Umntu omele intengiso |
Ukucokisa iziphumo ezingaphezulu, ungongeza isigaba somthetho:
UKUQALA I-FirstName, Igama lokugqibela kwi-Employees
NJANI IXALA = 'iTacoma';
Ibuyisela i-FirstName kunye neNameName yomntu ngamnye ovela kwi-Tacoma:
| Igama lokuqala | Ifani |
|---|---|
| Andrew | Epheleleyo |
Qaphela ukuba i-SQL ibuyisa idatha kwifom yekholam / ikholomu efana ne-Microsoft Excel, eyenza kube lula ukuyijonga nokusebenza nayo. Ezinye iilwimi zemibuzo zingabuya idatha njengegrafu okanye isati.
Amandla emibuzo
Isiseko sedatha sinokukwazi ukubonakalisa iimeko eziyinkimbinkimbi kunye nemisebenzi, kodwa la magunya asebenza kuphela ngokusetyenziswa kombuzo. Idatha edibeneyo iqukethe iitafile ezininzi ezigcinayo ezininzi zeenkcukacha. Umbuzo uvumela ukuwuhluza kwitafile enye ukuze uhlalutye ngokulula.
Imibuzo nayo ingenza izibalo kwi-data yakho okanye yenza imisebenzi yokulawula idatha. Unokuphinda ubuyekeze ukuhlaziywa kwedatha yakho ngaphambi kokuba ubenze kwi database.