Cov txheej txheem:
Video: Kuv yuav xaiv cov ntaub ntawv duplicate hauv MySQL li cas?
2024 Tus sau: Lynn Donovan | [email protected]. Kawg hloov kho: 2023-12-15 23:47
Nrhiav qhov tseem ceeb dua nyob rau hauv ib kem ntawm ib lub rooj, koj siv ua raws li cov kauj ruam no:
- Ua ntej, siv GROUP BY clause los pab pawg tag nrho kab los ntawm lub hom phiaj kab, uas yog kab uas koj xav mus xyuas luam tawm .
- Tom qab ntawd, siv COUNT() ua haujlwm hauv HAVING clause los xyuas seb ib pawg twg muaj ntau tshaj 1 lub ntsiab lus.
Ua raws li qhov no saib, kuv yuav ua li cas tso saib tsuas yog cov ntaub ntawv duplicate hauv SQL?
Xaiv count(*) AS count_, favorite_color_ FROM person_ GROUP BY favorite_color_ HAVING count(*) > 1 ORDER BY count_ DESC; Cov suav (*) hais kom ua yog ib qho kev ua haujlwm sib sau txhawb nqa los ntawm Postgres thiab muab cov naj npawb ntawm kab nrog duplicate nqi nyob rau hauv ib kem teev los ntawm GROUP BY clause.
Tom qab ntawd, lo lus nug yog, yuav ua li cas thiaj li tshem tau cov kab duplicate? Tshem tawm cov nqi sib npaug
- Xaiv qhov ntau ntawm cov cell, los yog xyuas kom meej tias lub cell active nyob rau hauv ib lub rooj.
- Ntawm cov ntaub ntawv tab, nyem Tshem Tawm Duplicates.
- Nyob rau hauv lub Remove Duplicates dialog box, unselect tej kab uas koj tsis xav kom tshem tawm duplicate nqi.
- Nyem OK, thiab cov lus yuav tshwm sim los qhia tias muaj pes tsawg tus nqi duplicate raug tshem tawm.
Yog li ntawd, kuv tuaj yeem rho tawm cov ntaub ntawv duplicate hauv mysql li cas?
Tsim ib lub rooj tshiab nrog cov qauv zoo ib yam li cov lus qub uas koj xav tau rho tawm duplicate kab . Ntxig qhov txawv kab los ntawm thawj lub rooj mus rau lub rooj tam sim. Tso lub rooj qub thiab hloov lub npe tam sim ntawd rau lub rooj qub.
Kuv yuav nrhiav tau cov duplicates hauv SQL li cas?
Nws ua haujlwm li cas:
- Ua ntej, GROUP BY clause pab pawg kab rau hauv pab pawg los ntawm qhov tseem ceeb hauv ob kab a thiab b.
- Qhov thib ob, COUNT() muaj nuj nqi rov qab tus naj npawb ntawm qhov tshwm sim ntawm txhua pab pawg (a, b).
- Thib peb, HAVING clause khaws tsuas yog pawg sib npaug, uas yog pawg uas muaj ntau dua ib qho tshwm sim.
Pom zoo:
Kuv yuav ua li cas xaiv cov kev xaiv hauv Word?
Xaiv cov ntsiab lus tswj, thiab tom qab ntawd xaiv Properties. Txhawm rau tsim ib daim ntawv teev cov kev xaiv, xaiv Ntxiv rau hauv Drop-Down List Properties. Ntaus ib qho kev xaiv hauv Lub Npe, xws li Yog, Tsis yog, lossis Tej zaum. Rov ua cov kauj ruam no kom txog thaum tag nrho cov kev xaiv nyob rau hauv daim ntawv teev npe
Kuv yuav hloov cov ntaub ntawv tab delimited rau cov ntaub ntawv csv li cas?
Mus rau cov ntawv qhia zaub mov, xaiv 'OpenCSVTab-Delimited File' (lossis tsuas yog nias Ctrl + O), thiab tom qab ntawd los ntawm lub thawv qhib, xaiv cov ntaub ntawv tab-delimited qhib. Koj tuaj yeem luam cov tab-delimited txoj hlua mus rau clipboard thiab tom qab ntawd siv 'Qhib Cov Ntawv Hauv Cov Ntawv Teev Npe' xaiv (Ctrl + F7)
Kuv yuav ua li cas thiaj tsim tau ZIP cov ntaub ntawv nrog ntau cov ntaub ntawv?
Muab ob peb cov ntaub ntawv mus rau hauv ib qho zippedfolder kom yooj yim sib faib ib pawg ntawm cov ntaub ntawv. Nrhiav cov ntaub ntawv lossis nplaub tshev uas koj xav zip. Nias thiab tuav (lossis right-click) cov ntaub ntawv lossis ntawv tais ceev tseg, xaiv (lossis taw tes rau) Xa mus rau, thiab tom qab ntawd xaiv Compressed (zipped) folder
Vim li cas kem taw qhia cov ntaub ntawv khaws cia ua cov ntaub ntawv nkag ntawm disks sai dua li kab qhia cov ntaub ntawv khaws cia?
Kem oriented databases (aka columnar databases) yog qhov tsim nyog rau kev ntsuas kev ua haujlwm ntau dua vim tias cov ntaub ntawv hom ntawv (kem hom) qiv nws tus kheej kom nrawm dua cov lus nug ua - scans, aggregation thiab lwm yam. Ntawm qhov tod tes, kab oriented databases khaws ib kab (thiab tag nrho nws. kab) contiguously
Kuv yuav ntxig cov ntaub ntawv WAV rau hauv cov ntaub ntawv Word li cas?
Ntxig ib lub suab ntaub ntawv rau hauv koj cov ntaub ntawv txoj hauj lwm qhov ntxig taw tes uas koj xav kom lub soundinserted. Xaiv Object los ntawm Insert. Worddisplays Object dialog box. Nyem rau ntawm Tsim los ntawm Cov Ntaub Ntawv tab. (Saib daim duab 1.) Siv cov kev tswj ntawm lub dialog box los nrhiav cov ntaub ntawv suab uas koj xav tau nrog rau koj cov ntaub ntawv. Nyem rau OK