Kugwiritsira ntchito zinyama zamasamba kuti zisagwirizane mofanana
Kufanana kwa SQL kufanana kumakulolani kuti mufufuze mapepala mu deta, ngati simukudziwa mawu enieni kapena mawu omwe mukufuna. Funso la SQL la mtundu uwu limagwiritsa ntchito zilembo za wildcard kuti zigwirizane ndi chitsanzo, m'malo momveka bwino. Mwachitsanzo, mungagwiritse ntchito wildcard "C%" kuti mufanane ndi chingwe chilichonse kuyambira ndikulu C.
Pogwiritsa ntchito LIKE Operator
Kuti mugwiritse ntchito mawu a wildcard mu funso la SQL, gwiritsani ntchito OPEREKEZA ofanana mu chigamulo cha WHERE, ndipo mutseke chitsanzocho m'malemba amodzi.
Pogwiritsa ntchito% Wildcard kuti Pangani Kafukufuku Wosavuta
Kuti mufufuze wogwira ntchito aliyense m'dongosolo lanu lachinsinsi ali ndi dzina lomaliza kuyambira ndi kalata C, gwiritsani ntchito mawu otsatirawa a Transact-SQL:
CHISANKHO * KUCHOKERA OTHANDIZA PAMENE last_name LIKHA 'C%'Kutsitsa Zithunzi Pogwiritsa Ntchito NOT Keyword
Gwiritsani ntchito mawu osasankhidwa kuti musankhe zolemba zomwe sizikugwirizana ndi chitsanzocho. Mwachitsanzo, funsoli limabweretsera malemba onse omwe dzina lawo limayamba ndi C:
CHISANKHO * KUCHOKERA OTHANDIZA PAMENE repot_name SIYE 'C%'Zitsanzo Zofanana Pogwiritsa Ntchito% Wildcard Kawiri
Gwiritsani ntchito maulendo awiri a % wildcard kuti mufanane ndi mtundu wina uliwonse. Chitsanzo ichi chibwezeretsa zolemba zonse zomwe ziri ndi C kulikonse mu dzina lomaliza:
CHISANKHO * KUYAMBIRA antchito WHERE last_name NGATI '% C%'Kupeza Mchitidwe Wotsanzira pa Malo Odziwika
Gwiritsani ntchito _ wildcard kuti mubwerere deta kumalo enaake. Chitsanzo ichi chikugwirizana kokha ngati C ikupezeka pamalo achitatu a chigawo chotsiriza:
CHISANKHO * KUYAMBIRA antchito WHERE last_name NGATI '_ _C%'Mawu a Wildcard athandizidwa pa Otsutsana SQL
Pali zinyama zambiri zakutchire zothandizidwa ndi Transact SQL:
- % Wildcard ikufanana ndi zero kapena zilembo zamtundu uliwonse, ndipo zingagwiritsidwe ntchito kufotokozera zikwangwani mapepala asanakhale ndi pambuyo pake. Ngati mumadziŵa bwino DOS chitsanzo, ndizofanana ndi * wildcard mu syntax.
- The _ wildcard imatsutsana chimodzimodzi khalidwe limodzi la mtundu uliwonse. Ndizofanana ndi ? wildcard mu DOS chitsanzo chofanana.
- Tchulani mndandanda wa malemba powaika iwo mu makina okhwima. Mwachitsanzo, wildcard [aeiou] ikugwirizana ndi vowel iliyonse.
- Tchulani mitundu yosiyanasiyana ya zilembo mwa kutsegula zoyimika mu mabakiteriya. Mwachitsanzo, wildcard [i] imafanana ndi kalata iliyonse kumapeto kwa zilembo.
- Sinthani zilembo zambiri mwa kuphatikizapo khalidwe la carat nthawi yomweyo mkati mwa bolodi yoyambira. Mwachitsanzo, [^ aeiou] amatsanzira khalidwe lililonse losakhala vola pamene [^ am] likugwirizana ndi khalidwe lililonse lomwe silinali gawo loyamba la zilembo.
Kuphatikiza Masikiti Akhazikitsa Zitsanzo Zovuta
Gwirizanitsani zikondwerero izi muzovuta kupanga mafunso apamwamba kwambiri. Mwachitsanzo, tiyerekeze kuti mukufunika kulemba mndandanda wa antchito anu onse omwe ali ndi mayina omwe amayamba ndi kalata kuchokera ku theka lachilembo koma samatha ndi vowel. Mungagwiritse ntchito funso ili:
CHISANKHO * CHOKERA KWA antchito WHERE last_name NGATI '[am]% [^ aeiou]'Mofananamo, mungathe kulemba mndandanda wa antchito onse omwe ali ndi mayina omalizira omwe ali ndi zigawo zinayi mwa kugwiritsa ntchito machitidwe anayi a _ chitsanzo:
CHISANKHO * KUYAMBIRA antchito WHERE last_name NGATI '____'Monga momwe mungathere, kugwiritsa ntchito SQL zitsanzo zofanana zimapereka ogwiritsa ntchito deta lachinsinsi kuti athe kupita kupyola mafunso osavuta alemba ndi kuchita ntchito yopita patsogolo.