Video: Dab tsi yog hloov ua haujlwm hauv SQL Server?
2024 Tus sau: Lynn Donovan | [email protected]. Kawg hloov kho: 2023-12-15 23:47
Kev piav qhia. Hauv SQL Server (Kev lag luam- SQL ntawv ), cov Hloov ua haujlwm converts ib qho kev qhia los ntawm ib datatype mus rau lwm datatype. Yog tias hloov dua siab tshiab poob, cov muaj nuj nqi yuav rov qab ua yuam kev. Txwv tsis pub, nws yuav rov qab hloov dua siab tshiab tus nqi.
Ib yam li ntawd, tib neeg nug, qhov txawv ntawm convert () thiab hom () muaj nuj nqi yog dab tsi?
Style tso cai formatting cov ntaub ntawv hom thiab qhia tias yuav ua li cas cov Hloov ua haujlwm yuav tsum txhais los yog hom ntawv hom ntaub ntawv. Cov Hloov ua haujlwm tsis xav tau ib lo lus tseem ceeb los cais cov txiaj ntsig thiab hom ntaub ntawv.
Ib yam li ntawd, peb puas tuaj yeem hloov varchar rau int hauv SQL? Rau hloov a Varch to INT siv sql conversion ua haujlwm zoo li pov tseg los yog hloov.
Ua kom pom qhov no, CAST muaj nuj nqi dab tsi hauv SQL Server?
Ntxig () Muaj nuj nqi hauv SQL Server Cov Ntxig () muaj nuj nqi yog siv los hloov cov ntaub ntawv hom hloov pauv lossis cov ntaub ntawv los ntawm ib hom ntaub ntawv mus rau lwm hom ntaub ntawv. Cov Ntxig () muaj nuj nqi muab ib hom ntaub ntawv rau ib tug dynamic parameter (?) lossis tus nqi NULL. Hom ntaub ntawv uas koj yog casting ib qho kev nthuav qhia yog hom phiaj.
Peb puas tuaj yeem hloov varchar rau hnub tim hauv SQL?
Cov hloov dua siab tshiab ntawm a varchar hom ntaub ntawv rau a hnub tim hom ntaub ntawv ua rau muaj qhov tsis muaj nuj nqis. Koj xav tau cov separators rau cov hnub zoo li "/", "." los yog "-". Peb siv substring los concatenate lub "-" siv tau hnub format thiab ces peb siv cov Hloov pauv ua haujlwm rau hloov cov cim rau sql hnub.
Pom zoo:
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