Mtsogoleli Wogwiritsira Ntchito Zowumikizana Kwawo Pakati pa SQL ku Gulu la Data kuchokera ku Matebulo Ambiri

Gwiritsani ntchito Zowonjezera Zowonjezera SQL kuphatikiza data kuchokera pa matebulo atatu kapena angapo

Mukhoza kugwiritsa ntchito mawu a SQL JOIN kuti muphatikize data kuchokera pa matebulo atatu kapena angapo. SQL JOIN imasinthasintha kwambiri, ndipo ntchito zake zamphamvu zingagwiritsidwe ntchito kuphatikiza deta kuchokera pa matebulo angapo. Tiyeni tiwone mawu a SQL omwe amakulolani kuti muphatikize zotsatira kuchokera ku matebulo atatu osiyanasiyana pogwiritsa ntchito mgwirizano wamkati.

Chitsanzo Chojambulira Pakati

Mwachitsanzo, tengani matebulo omwe ali ndi madalaivala pa tebulo limodzi ndi magalimoto pamasewera achiwiri. Mgwirizano wamkati umapezeka kumene galimoto ndi dalaivala zili mumzinda womwewo. Cholowa chamkati chimasankha mizere yonse kuchokera pa matebulo onse omwe ali ndi machesi pakati pa zigawo za malo.

Ndemanga ya SQL pansiyi ikuphatikiza deta kuchokera kwa madalaivala ndi magalimoto magalimoto pomwe madalaivala ndi galimoto ali mumzinda womwewo:

SELECT lastname, firstname, tag KUYENDA madalaivala, magalimoto PAMENE madalaivala.location = magalimoto.malo

Funso ili limapanga zotsatira zotsatirazi:

Baker Roland H122JM Smythe Michael D824HA Smythe Michael P091YF Jacobs Abraham J291QR Jacobs Abraham L990MT Zoyenera Kutsatira Nkhani Yosunga Chinsinsi Foni ya M'manja Zimene Mumakonda Manambala a Masamba Kukula kwa Zilembo

Tsopano, perekani chitsanzo ichi kuti muphatikize tebulo lachitatu. Tangoganizani kuti mukufuna kuti mukhale ndi madalaivala okha ndi magalimoto omwe ali pamalo omwe ali otsegulidwa pa sabata. Mukhoza kubweretsa tebulo lachitatu mu funso lanu powonjezera ndondomeko ya JOIN motere:

SELECT lastname, firstname, tag, open_weekends kuchokera ku madalaivala, magalimoto, malo OYENDA madalaivala.location = magalimoto.madera ndi magalimoto.location = malo.madera ndi malo.open_weekends = 'Inde' dzina lake firstname tag open_weekends -------- Baker Roland H122JM Inde Yakobos Abraham J291QR Inde Jacobs Abraham L990MT inde

Kuwonjezera kwamphamvu kwa mfundo yoyamba ya SQL JOIN kumakupatsani inu kuphatikiza deta mwanjira yovuta. Kuphatikiza pa kuphatikiza matebulo okhala ndi mgwirizano wamkati, mungagwiritsenso ntchito njirayi kuphatikiza matebulo ambiri pogwiritsa ntchito mgwirizano wakunja. Zowonjezera kunja zimaphatikizapo zotsatira zomwe ziri patebulo limodzi koma alibe chofanana chofanana mu tebulo lophatikizidwa.