Video: Puas yog SQL hloov cov ntaub ntawv nkag siab?
2024 Tus sau: Lynn Donovan | [email protected]. Kawg hloov kho: 2023-12-15 23:47
SQL ntawv Server Case Sensitive Hloov
(Lub Hloov muaj nuj nqi tiag tiag siv lub neej ntawd collation ntawm cov ntawv sau uas nws tab tom nrhiav). Tig nws mus rau a SQL ntawv Server case sensitive hloov , peb tsuas yog yuav tsum tau ntxiv ib qho me me mus rau qhov kawg.
Ib yam li ntawd, nws tau nug, puas yog MySQL hloov cov ntaub ntawv nkag siab?
MySQL REPLACE () Function Cov Hloov () muaj nuj nqi hloov tag nrho cov tshwm sim ntawm ib tug substring nyob rau hauv ib txoj hlua, nrog ib tug tshiab substring. Nco tseg: Cov haujlwm no ua haujlwm a cas - rhiab heev hloov.
Ib yam li ntawd, koj hloov cov ntaub ntawv li cas hauv lub rooj SQL? SQL UPDATE syntax
- Ua ntej, qhia lub npe lub rooj uas koj xav hloov cov ntaub ntawv hauv UPDATE clause.
- Thib ob, muab tus nqi tshiab rau kab uas koj xav hloov tshiab.
- Thib peb, qhia cov kab twg koj xav hloov tshiab hauv WHERE clause.
Ntawm no, Hloov ua haujlwm hauv SQL yog dab tsi?
SQL muab kev pab zoo heev txoj hlua muaj nuj nqi hu ua REPLACE uas tso cai rau koj los hloov txhua qhov tshwm sim ntawm substring hauv a txoj hlua nrog ib tug tshiab substring. REPLACE( txoj hlua , old_substring, new_substring); REPLACE muaj nuj nqi yuav tshawb nrhiav txhua qhov tshwm sim ntawm old_substring thiab hloov nws nrog tus tshiab_string.
Kuv yuav rho tawm tus cim hauv SQL li cas?
Cov TRIM () muaj nuj nqi tshem tawm qhov chaw tus cwj pwm LOSSIS lwm yam teev tseg cov cim los ntawm qhov pib lossis xaus ntawm ib txoj hlua. Los ntawm default, lub TRIM () muaj nuj nqi tshem tawm qhov ua ntej thiab tom qab ntawm ib txoj hlua. Nco tseg: Kuj saib LTRIM() thiab RTRIM() ua haujlwm.
Pom zoo:
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