Kushandisa Wildcards yeInxact Kubatana
SQL muenzaniso inofanirwa inokubvumira kutsvaga mapepa munharaunda, kana iwe usingazivi izwi chaiyo kana mutsara wauri kutsvaga. Iri rudzi rweSQL runoshandisa sarcard characters kutevedzera purogiramu, pane kungojekesa chaizvo. Somuenzaniso, unogona kushandisa wildcard "C%" kuti ifanane chero tambo yakatanga neC.
Kushandisa SEMEI Operator
Kuti ushandise kutaura kweparkcard mubvunzo weSQL, shandisa shanduro inofanirwa mune imwe ndima WHERE, uye uvhare iyo purogiramu mukati memavhaisiro maviri ezvinyorwa.
Kushandisa% Wildcard Kuti Uite Tsvakurudzo Yakajeka
Kuti utsvake chero mushandi mune database yako ane zita rekupedzisira anotanga netsamba C, shandisa izwi rinotevera reTractact-SQL:
Sarudza * KUBVA kuvashandi WHERE last_name IYE 'C%'Kusiya Maitiro Kushandisa IAS Keyword
Shandisa HERE musimboti kuti usarudze zvinyorwa zvisingafananidzi purogiramu. Semuenzaniso, mubvunzo uyu unodzorera zvose zvinyorwa zvine zita rekupedzisira risina kutanga neC:
Sarudza * Kubva vashandi PAPA last_name HAKASI 'C%'Kutarisa Muenzaniso Pamwe Chekushandisa% Wildcard Kaviri
Shandisai miviri miviri ye % wildcard kuti muenzane neimwe nzira chero ipi zvayo. Uyu muenzaniso unodzorera zvose zvinyorwa zvine C pane chero kupi zvako muzita rekupedzisira:
Sarudza * KUBVA kuvashandi PAPERE last_name LIKE '% C%'Kutsvaga Muenzaniso Wekufananidzira pane Chimiro Chaicho
Shandisai _ wildcard kudzorera data pane imwe nzvimbo. Uyu muenzaniso unofananidzwa chete kana C inowanikwa panzvimbo yechitatu yezita rekupedzisira koromo:
Sarudza * KUBVA kuvashandi WHERE last_name LIKE '_ _C%'Yakatsigirwa Zvinyorwa zveClecard inotenderera SQL
Iko kune mhando dzakasiyana dzesango dzinotsigirwa neTransact SQL:
- I % wildcard inosangana zero kana kuti mamwe mavara emhando ipi zvayo, uye inogona kushandiswa kutsanangura chikwangwani chekare nemushure pemaitiro. Kana iwe uchiziva neDOS pattern inofananidzwa, ndiyo yakaenzana ne * wildcard mune iyo syntax.
- I-wildcard inobatana zvakafanana nehupi hwemhando ipi zvayo. Ndiyo yakaenzana neyo ? wildcard muDOS pattern inoenderana.
- Rondedzera urongwa hwevanhu vakagadzwa nokuvavhara pakabhejikiti. Somuenzaniso, wildcard [aeiou] inobatanidza chero vowel.
- Rondedzera huwandu hwevanhu vakagadzikana nekuvhara rutsanga pakabhejikiti. Somuenzaniso, wildcard [ine] inobatanidza tsamba chero ipi zvayo muhafu yekutanga yezvinyorwa.
- Sora huwandu hwevanhu kuburikidza nekubatanidza chimiro cha carat munguva pfupi mukati mekuvhara kwekona. Semuenzaniso, [^ aeiou] inobatanidza chero chipi zvacho chisina mutauro kana [...] chichifananidza chero hutsika kwete muhafu yekutanga yezvinyorwa.
Kubatanidza Wildcards neKushanda Maitiro
Gadzirai mapurcard aya mumitambo yakaoma kuti muite mibvunzo yakanyanyisa. Somuenzaniso, ngatiti iwe unoda kuvaka runyoro rwevashandi vako vose vane mazita anotanga netsamba kubva pahafu yekutanga yezvinyorwa asi haagumi nevhavha. Iwe unogona kushandisa chirevo chinotevera:
Sarudza * KUBVA kuvashandi WHERE last_name LIKE '[am]% [^ aeiou]'Saizvozvowo, unogona kuvaka runyoro rwevashandi vose nemazita ekupedzisira ane mavara mana chaiwo achishandisa zviitiko zvina zve_i pattern:
Sarudza * Kubva vashandi PAPA last_name LIKE '____'Sezvaunogona kuudza, kushandiswa kweSQL kuenzanirana nehutano kunopa vashandisi vepa database vanokwanisa kuenda kunze kwemibvunzo yemavara uye kuita mabasa ekutsvakurudza.