Cov txheej txheem:
Video: Kuv yuav ua li cas kom kuv SQL code nyeem tau?
2024 Tus sau: Lynn Donovan | [email protected]. Kawg hloov kho: 2023-12-15 23:47
Yog li, tau kawg ntawm no yog qee qhov kuv tus kheej cov lus pom zoo yuav ua li cas kom SQL nyeem tau ntau dua
- Ib yam rau kab. Tsuas yog muab ib kab / rooj / koom ib kab.
- Kho koj qhov projections thiab tej yam kev mob.
- Siv cov npe kab ke thaum pab pawg / xaj.
- Cov lus pom.
- Casing.
- CTEs.
- Xaus.
Tsuas yog li ntawd, kuv yuav ua li cas khiav SQL code?
Txhawm rau ua cov ntawv sau los ntawm nplooj ntawv SQL Scripts:
- Ntawm nplooj ntawv chaw ua haujlwm, nyem SQL Rhiav thiab tom qab ntawd SQL Scripts.
- Los ntawm Saib daim ntawv teev npe, xaiv Cov Lus Qhia thiab nyem Mus.
- Nyem rau Khiav icon rau tsab ntawv koj xav ua.
- Nplooj ntawv Run Script tshwm.
- Nyem Khiav kom xa tsab ntawv rau kev ua tiav.
Ib yam li ntawd, kuv yuav qhwv cov ntawv hauv SQL lus nug qhov rai li cas? Txhawm rau qhib lo lus qhwv
- Nyem Options ntawm cov cuab yeej ntawv qhia zaub mov.
- Nyem Text Editor.
- Qhib cov ntawv tais ceev tseg uas tsim nyog (lossis Txhua Hom Lus cuam tshuam rau txhua hom lus).
- Xaiv lo lus qhwv.
Ua li no, ua li cas koj sau SQL code zoo?
Nov yog qee cov lus qhia thiab kev coj ua zoo tshaj plaws rau txhua qhov kev txhim kho SQL
- Xav txog kev sib raug zoo.
- Ib txwm xav txog kev ua tau zoo, txawm tias cov lus nug zoo li yooj yim.
- SIV TABLE ALIASES kom nyeem tau yooj yim dua.
- Ua tshwj xeeb hauv koj cov SELECT Clauses.
- Siv NOCOUNT rau cov lus nug loj.
- Tsis txhob Dynamic SQL.
- Tsis txhob hnov qab Object-Level Security.
Yuav ua li cas koj optimize cov lus nug?
Ua raws li SQL cov kev coj ua zoo tshaj plaws los xyuas kom meej cov lus nug optimization:
- Index tag nrho cov predicates nyob rau hauv JOIN, qhov twg, ORDER BY thiab GROUP BY clauses.
- Tsis txhob siv cov haujlwm hauv cov lus qhia.
- Tsis txhob siv wildcard (%) thaum pib ntawm qhov ua piv txwv.
- Zam cov kab tsis tsim nyog hauv SELECT clause.
- Siv cov koom nrog sab hauv, tsis yog kev koom nrog sab nraud yog tias ua tau.
Pom zoo:
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