Jagora don Amfani da Inner shiga cikin SQL zuwa Rukunin Rukunin daga Ɗaukaka Tables

Yi amfani da SQL Inner shiga don hada bayanai daga uku ko fiye da Tables

Zaka iya amfani da maganganun JININ SQL don hada bayanai daga matuka uku ko fiye. SANTA SQL yana da cikakkun sauƙi, kuma ana iya amfani da ikonsa don hada bayanai daga launi masu yawa. Bari mu dubi maganganun SQL wanda ke ba ka damar haɗa sakamakon daga matakai daban daban uku ta amfani da haɗin ciki.

Abinda ke ciki shiga misali

Alal misali, ɗauki tebur da ke dauke da direbobi a teburin daya da abin hawa a cikin na biyu. Abinda ke ciki yana faruwa a inda duk abin hawa da direba sun kasance a cikin wannan birni. Tsakanin ciki yana zaɓar dukkan layuka daga duka tebur wanda ya ƙunshi wasa tsakanin ginshiƙan wurare.

Bayanin SQL ɗin da ke ƙasa ya haɗo bayanai daga Rukunin motoci da motoci a lokuta inda direba da abin hawa suna cikin birni guda:

SANTA sunan mai suna, sunan farko, tag DAGA direbobi, motocin WANTA direbobi.location = motoci.location

Wannan tambayar ya haifar da sakamakon da ya biyo baya:

namename firstname tag --------------------- --- Baker Roland H122JM Shine Michael D824HA Tsohon Michael P091YF Jacobs Ibrahim J291QR Jacobs Ibrahim L990MT

Yanzu, mika wannan misali don haɗawa da tebur na uku. Ka yi tunanin cewa kana son hadawa kawai direbobi da motocin da ke wurin a wurare da suke bude a karshen mako. Kuna iya kawo matuka na uku a cikin tambayarka ta hanyar fadada bayanin JOIN kamar haka:

BABI sunan mai suna, sunan farko, tag, budewa daga DA direbobi, motoci, wurare AYAN direbobi.location = motoci da kuma motoci.location = wurare.location AND places.open_weekends = 'Ee' sunan mai suna firstname tag open_weekends -------- --------- --- --------------- Baker Roland H122JM a Jacobs Ibrahim J291QR a Jacobs Ibrahim L990MT a

Wannan ƙwararren ƙarfin da ke cikin asali na SQL SAN bayani yana ba ka damar hada bayanai a cikin hanyar hadari. Bugu da ƙari ga hada da tebur da ƙungiyar ciki, zaka iya amfani da wannan ƙira don haɗuwa da tebur da yawa ta yin amfani da haɗin waje. Outer sun hada da sakamakon da suke cikin tebur ɗaya amma basu da daidaito a cikin layin da aka haɗa.