Gabatar da WAƊAN sashi da kuma BABA yanayin
Harshen Sakamakon Bincike (SQL) yana ba masu amfani da bayanai damar da za su iya ƙirƙirar tambayoyin da aka ƙayyade don cire bayanai daga bayanan bayanai. A cikin labarin da suka gabata, mun bincika samo bayanan daga bayanai ta amfani da tambayoyi na SQL SELECT . Bari mu fadada a kan wannan tattaunawa da kuma gano yadda za ku iya gudanar da tambayoyin da aka ci gaba don dawo da bayanan da ya dace da yanayi.
Bari muyi la'akari da misalin da aka yi amfani da tushen Arewawindow, wanda ke amfani da samfurori tare da samfurori na asali.
Ga wani samfurin daga database na Teburin samfurin:
| ProductID | Sunan Sunan | SupplierID | YawanTaɗaya | UnitPrice | UnitsInStock |
|---|---|---|---|---|---|
| 1 | Chai | 1 | 10 kwalaye x 20 bags | 18.00 | 39 |
| 2 | Chang | 1 | 24 - 12 tabarbalan gas | 19.00 | 17 |
| 3 | Sugar Aniseed | 1 | 12 - 550 ml kwalabe | 10.00 | 13 |
| 4 | Chef Anton na Cajun Seasoning | 2 | 48 - 6 na kwalba | 22.00 | 53 |
| 5 | Chef Anton's Gumbo Mix | 2 | 36 kwalaye | 21.35 | 0 |
| 6 | Grandma ta Boysenberry yada | 3 | 12 - 8 oz kwalba | 25.00 | 120 |
| 7 | Uncle Bob's Organic Dried Pears | 3 | 12 - 1 lb pkgs. | 30.00 | 15 |
Ƙayyadaddun Yanayi
Ƙuntatawa na farko da za mu sanya a kan bincikenmu sun ƙunshi yanayi na iyakance mai sauki. Za mu iya ƙayyade waɗannan a cikin WANNAN SABARI na tambaya SELECT, ta amfani da maganganun maganganu masu sauki wanda aka gina tare da masu aiki na kwarai, kamar <,>,> =, da <=.
Da farko, bari mu gwada tambaya mai sauƙi wanda ya ba mu damar cire jerin abubuwan da ke cikin cikin bayanan da ke dauke da UnitPrice na fiye da 20.00:
Wannan yana samar da jerin samfurori huɗu, kamar yadda aka nuna a kasa:
Kayan Wurin Kayan Lissafi na Yanar Gizo --------------- Babbar Anton's Gumbo Mix 21.35 Babbar Wakilin Anton na Cajun Sabuwar yanayi 22.00 Mahaifiyarta ta Boysenberry Taba 25.00 Uncle Bob's Organic Dried Pears 30.00Hakanan zamu iya amfani da sashin WHERE tare da dabi'u mai launi. Wannan nau'in haruffa daidai ne zuwa lambobi, tare da A yana wakiltar darajar 1 da Z suna wakiltar darajar 26. Alal misali, zamu iya nuna duk samfurori tare da sunaye da suka fara da U, V, W, X, Y ko Z tare da tambaya mai zuwa:
Sake samfurin LATTA DAGA samfurori YA SAMA GABARI> = 'T'Wanne ya haifar da sakamakon:
Sunan Kyauta ------- Ƙwararren Abun Gudun Daji na BobBayyana Ranges ta yin amfani da Boundaries
Wurin SANTA yana ba mu damar aiwatar da yanayi mai mahimmanci a kan darajar ta amfani da yanayi mai yawa. Alal misali, idan muna so mu dauki tambayoyinmu a sama da kuma iyakance sakamakon zuwa samfurori tare da farashin tsakanin 15.00 da 20.00, zamu iya amfani da wannan tambaya:
Sake Kayan samfurin, Kayan aiki daga samfurori YA ZUWARIWARI> 1500 DA SUNIYA <20.00Wannan yana haifar da sakamakon da aka nuna a kasa:
Sakamakon Kamfani na Ƙirƙirar na'urori -------------------------------------------------------------------------------------------------------------Bayyana Ranges tare da BABI
SQL kuma yana bayar da gajeren hanya BABI haɗin gwiwar da ke rage yawan yanayin da muke buƙatar haɗawa da kuma sa tambaya ta fi dacewa. Alal misali, maimakon yin amfani da sharuɗɗan ABERE guda biyu a sama, zamu iya bayyana wannan tambayar kamar haka:
Sake Kayan samfurin, Kayan aiki daga samfurori DA GASKIYA SANAR DA KUMA 1500 DA 20.00Kamar yadda muke da sauran ka'idojinmu, ABUBUKA yana aiki tare da dabi'u mai mahimmanci. Idan muna son samar da jerin sunayen ƙasashe da suka fara da V, W ko X, za mu iya amfani da tambaya:
Sake samfurin LITTAFI DAGA samfurori BAYANNAN SANTA DA "A" da "D"Wanne ya haifar da sakamakon:
Sunan Kyauta ------- Maganin Aniseed Chai Chang Chef na Anton's Gumbo Mix Sabon Anton na Cajun SeasoningWANNAN SANTA wani ɓangare ne na harshen SQL wanda ke ba ka damar ƙuntata sakamakon zuwa dabi'u da ke fadi a cikin jeri. Ana amfani dashi sosai don taimakawa wajen bayyana tsarin basirar kasuwanci kuma ya kamata ya kasance wani ɓangare na kayan aiki na masu sana'a na ƙididdiga.
Yawancin lokaci yana taimakawa wajen sanya ka'idodi na gari a cikin hanyar da aka adana don sa ta kasancewa ga waɗanda ba tare da ilmi na SQL ba.