Video: Cov lus nug pivot hauv SQL yog dab tsi?
2024 Tus sau: Lynn Donovan | [email protected]. Kawg hloov kho: 2023-12-15 23:47
Lub hom phiaj ntawm cov PIAV query yog tig cov zis thiab tso saib cov ntaub ntawv ntsug horizontally. Cov no lus nug tseem hu ua crosstab lus nug . Cov SQL ntawv Server PIVOT tus neeg teb xov tooj tuaj yeem siv tau yooj yim tig / hloov koj cov ntaub ntawv. Qhov no yog ib qho cuab yeej zoo heev yog tias cov ntaub ntawv tseem ceeb uas koj xav tig tsis zoo li yuav hloov.
Tsis tas li ntawd, cov lus nug pivot yog dab tsi?
A PIAV query yog qhov tseem ceeb SELECT qhia cov kab uas koj xav tau thiab yuav ua li cas PIVOT thiab GROUP lawv.
Koj siv pivot thiab Unpivot hauv SQL li cas? Cov PIVOT nqe lus yog siv los hloov cov kab lus rau hauv kab, thaum lub UNPIVOT tus neeg teb xov tooj hloov cov kab rov qab mus rau kab. Rov qab a PIVOT nqe lus hais txog tus txheej txheem ntawm kev thov cov UNPIVOT tus neeg teb xov tooj mus rau qhov twb PIVOTED dataset thiaj li yuav rov qab tau cov ntaub ntawv qub.
Ib yam li ntawd, pivot hauv SQL Server nrog piv txwv yog dab tsi?
SQL Server PIVOT tus neeg teb xov tooj rotates lub rooj-valued qhia. Nws hloov cov nqi tshwj xeeb hauv ib kem mus rau ntau kab hauv cov zis thiab ua cov kev sib sau ua ke ntawm txhua qhov seem seem. Thib ob, tsim qhov tshwm sim ib ntus los ntawm kev siv lub rooj sib tham lossis cov lus qhia sib tham (CTE) Thib peb, siv lub PIVOT tus neeg ua haujlwm.
dynamic query yog dab tsi?
Cov lus nug dynamic xa mus rau lus nug uas yog tsim dynamically los ntawm Drupal es tsis yog muab raws li qhov tseeb nug txoj hlua. Tag nrho Insert, Update, Rho tawm, thiab Merge lus nug yuav tsum yog dynamic . Xaiv lus nug tej zaum yuav yog static los yog dynamic . Yog li ntawd, " dynamic lus nug "feem ntau yog hais txog a dynamic Xaiv nug.
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