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Max yog dab tsi hauv SQL?
Max yog dab tsi hauv SQL?

Video: Max yog dab tsi hauv SQL?

Video: Max yog dab tsi hauv SQL?
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MAX() muaj nuj nqi

Cov aggregate muaj nuj nqi SQL MAX() yog siv los nrhiav tus nqi siab tshaj plaws los yog tus nqi siab tshaj ntawm ib yam kem los yog kev qhia. Qhov no muaj nuj nqi yog pab tau los txiav txim qhov loj tshaj plaws ntawm tag nrho cov nqi xaiv ntawm a kem.

Dhau li ntawd, koj pom Max hauv SQL li cas?

Rau tau qhov siab tshaj plaws tus nqi ntawm ib kab zauv siv tus MAX () ua haujlwm. Xaiv MAX () Los ntawm

; Xaiv MAX () Los ntawm

UA NTEJ; Rau tau qhov tsawg kawg nkaus tus nqi ntawm ib kab zauv siv MIN() muaj nuj nqi.

Ib tug kuj nug, Kuv puas tuaj yeem siv Max nyob rau hauv qhov twg clause? SQL muaj CLAUS yog tseg rau aggregate muaj nuj nqi. Kev siv qhov twg lus nrog SQL MAX () kuj tau piav qhia hauv nplooj ntawv no. SQL IN OPERATOR uas kuaj xyuas tus nqi hauv ib txheej ntawm qhov tseem ceeb thiab muab cov kab los ntawm lub rooj ua tau kuj be siv nrog MAX muaj nuj nqi.

Kev sib raug zoo, tus nqi siab tshaj plaws ntawm kev ua haujlwm yog dab tsi?

Cov tus nqi siab tshaj ntawm a muaj nuj nqi yog qhov chaw a muaj nuj nqi mus txog nws qhov siab tshaj plaws, lossis vertex, ntawm ib daim duab. Piv txwv li, hauv daim duab no, lub tus nqi siab tshaj plaws ntawm kev ua haujlwm yog y5.

Kuv yuav xaiv thawj 5 kab hauv SQL li cas?

SQL SELECT TOP Clause

  1. SQL Server / MS Access Syntax. SELECT TOP tus naj npawb | feem pua npe column_name(s) NTAWM table_name;
  2. MySQL Syntax. SELECT column_name(s) NTAWM table_name. LIMIT tus lej;
  3. Piv txwv. SELECT * Los ntawm cov neeg. TXOJ CAI 5;
  4. Oracle Syntax. SELECT column_name(s) NTAWM table_name. THAUM ROWNUM <= tus lej;
  5. Piv txwv. SELECT * Los ntawm cov neeg.

Pom zoo: