Video: Dab tsi yog kev siv offset hauv MySQL?
2024 Tus sau: Lynn Donovan | [email protected]. Kawg hloov kho: 2023-12-15 23:47
MySQL TXOJ CAI OFFSET : Cov ntsiab lus
Koj ua tau siv nws kom paginate kab lus lossis lwm yam tswj cov ntaub ntawv ntau yam tsis muaj kev cuam tshuam kev ua haujlwm. Yog tias koj xav kom cov lus nug rov qab nkag pib los ntawm ib kab, koj tuaj yeem ua tau siv OFFSET clause qhia nws qhov twg nws yuav tsum pib.
Kuj kom paub yog, dab tsi yog kev siv offset hauv SQL?
OFFSET thiab FETCH yog siv xa rov qab lub qhov rais ntawm cov ntaub ntawv los ntawm qhov tshwm sim. OFFSET qhia tias muaj pes tsawg kab hla dhau qhov tshwm sim, thiab FETCH qhia tias muaj pes tsawg kab los ntawm qhov taw tes rau pem hauv ntej kom rov qab los ntawm qhov tshwm sim. OFFSET thiab FETCH tsis ntev los no tau qhia hauv SQL ntawv Server 2012 thiab yog raws li ANSI.
Tsis tas li ntawd, qhov txwv thiab offset hauv MySQL yog dab tsi? Hauv MySQL tus TXOJ CAI clause yog siv nrog SELECT nqe lus los txwv cov lej ntawm cov kab hauv qhov tshwm sim. Cov Txwv Clause lees txais ib lossis ob qhov kev sib cav uas yog offset thiab suav. Tus nqi ntawm ob qho kev ntsuas tuaj yeem yog xoom lossis cov lej zoo.
Raws li, MySQL offset yog dab tsi?
Taw qhia rau MySQL LIMIT clause LIMIT [ offset ,] row_ suav; Nyob rau hauv no syntax: The offset qhia cov offset ntawm thawj kab rov qab. Cov offset ntawm thawj kab yog 0, tsis yog 1. row_count qhia cov kab ntau tshaj plaws kom rov qab los.
Kuv yuav txwv cov ntaub ntawv hauv MySQL li cas?
Cov txwv lo lus tseem ceeb yog siv rau txwv tus lej ntawm kab xa rov qab rau hauv cov lus nug tshwm sim. "SELECT {fieldname(s) | *} FROM tableName(s)" yog SELECT nqe lus uas muaj cov teb uas peb xav rov qab rau hauv peb cov lus nug. "[Qhov xwm txheej]" yog xaiv tau tab sis thaum muab khoom, tuaj yeem siv los qhia meej lub lim ntawm qhov tshwm sim.
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