A Nduzi Iji Iji Nabata Na SQL na Group Data site na otutu tebụl

Jiri SQL N'ime Na-esonye ikpokọta data site na atọ ma ọ bụ karịa tebụl

Ị nwere ike iji SQL BỤ okwu iji jikọta data sitere na tebụl atọ ma ọ bụ karịa. SQL JOIN dị nnọọ mfe, yana ike ịrụ ọrụ dị ike iji jikọọ data sitere na tebụl ọtụtụ. Ka anyị lelee okwu SQL ndị na-enye gị ohere ijikọta nsonaazụ sitere na tebụl dị iche iche dị iche iche na-eji njikọ n'ime.

Na-esonye Ihe Nlereanya

Dịka ọmụmaatụ, buru tebụl ndị nwere ndị ọkwọ ụgbọala na otu tebụl na ụgbọala na-esote na nke abụọ. Ntinye n'ime etinyere ebe ma ụgbọala ma ọkwọ ụgbọala nọ n'otu obodo ahụ. Ntinye n'ime ya ahọrọ ahịrị niile site na tebụl ndị nwere egwuregwu n'etiti ebe obibi ebe.

Nkwupụta SQL ahụ na-agwakọta data sitere na tebụl ụgbọala na ụgbọ ala na ebe ebe ọkwọ ụgbọala na ụgbọala nọ n'otu obodo ahụ:

CHINE aha ọkpọ, aha mbụ, ndị na-ọkwọ ụgbọala na ndị uweojii AD, ndị ụgbọala ụgbọala ebe a

Ajụjụ a na-emepụta nsonaazụ ndị a:

aha njirimara aha -------- --------- --- Baker Roland H122JM Smythe Michael D824HA Smythe Michael P091YF Jacobs Abraham J291QR Jacobs Abraham L990MT

Ugbu a, gbasaa ihe atụ a iji tinye okpokoro atọ. Were ya na ịchọrọ itinye nanị ndị ọkwọ ụgbọala na ugbo ndị dị na ebe ndị na-emeghe na ngwụsị izu. I nwere ike iweta okpokoro nke atọ n'ime nyocha gị site na ịgbasa nkwupụta JOIN dị ka ndị a:

CHINE aha ọkpọ, aha mbụ, mkpado, nkwụsị nke ndị ọkwọ ụgbọala, ugbo ala, ọnọdụ ebe ọ bụ na drivers.location = ugbo ala na ụgbọala.location = location.location AND locations.open_weekends = 'Ee' aha mbụname tag open_weekends -------- --------- ---------------- Baker Roland H122JM ee Jacobs Abraham J291QR ee Jacobs Abraham L990MT ee

Mgbasapụ a dị ike na isi SQL JOIN nkwupụta na-enye gị ohere ijikọ data na mgbagwoju anya. Na mgbakwunye na ijikọta tebụl na njikọta n'ime, ị nwekwara ike iji usoro a iji jikọta tebụl ọtụtụ na-eji iji mbupụ. Njikọ ndị ọzọ na-agụnye nsonaazụ dị na otu tebụl ma enweghị egwuregwu kwekọrọ na tebụl esonyere.