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MySQL ??? ?????? InnoDB ?? ?? ???? ???????. ??, innodb_buffer_pool_size? 16GB? ????? 12G? ?? ?? ??? RAM? 70-80%? ???? ?? ???? 95%? ????????. ??, ?? ?? ? ??, innodb_buffer_pool_instances? 8?? ???? ??? ????. ?? ?? innodb_buffer_pool_dump_at_shutdown ? innodb_buffer_pool_load_at_startup? ????? ?? ??? ? ?? ? ???? ??? ?????. ????? ?? ? ?? ?? ????? ??????
Sep 11, 2025 pm 02:10 PM
MySQL????? ?????? ??
toupdateaview'sdefinitioninmysql, usealtervieworcreateorreplaceviewtomodify.2.toupdatedatathroughaview, useupdate, insert, ordeletestatementsiftheviewisupdatable, whatequiresittonotusedistby, whoal, subqueries, subqueries
Sep 11, 2025 am 11:01 AM
MySQL?? ??? ??? ??? ?? ??? ??????
seedescribectoCtoQuickLyViewColumnDetailSlikEname, type, andkeyInfo.2.QueryInfO.2.QueryInformation_schema.columnsforCustomizable, reveralmetAdata.3.useshOwReatEtableTeSeethefullTableCreationSql.4.usshowindextoreTreveInformation.
Sep 11, 2025 am 10:48 AM
MySQL? Performance_schema ??????? ??????
ThePerformance_schemadatabaseinmysqlprovideSreal-timeperformanmanmonitoringanddiagnosticsBytrackingserActivitiEssuchassQlStatementExecution, ThreadBehavior, FileI/O, TableAccess, ??, ??? ?? ? Waitevents;
Sep 11, 2025 am 10:26 AM
MySQL?? '?? ?? ??'??? ???? ??? ??????
CheckCurrentConnectionSagewithVariables like'max_connection'andshowstatus like'showstatus like'threads_connected'toconfirmifthelimitispeached
Sep 11, 2025 am 09:36 AM
MySQL?? ?? ?? ??? ??? ??????
to to thecreateignkeyInmysql, defineacolumnreencinganothertable? sprimaryoruniquekeyusingforeignkeyIncreateTableOraltertable, datatyypes, innodbengine ? indexeDeedReferencedColumns? ?????.
Sep 11, 2025 am 09:25 AM
MySQL ?? ??? ???? ??
runshowslavestatus \ gonthereplicatocheckreplicationstatus.2.verifyslave_io_running : ?, ???? _sql_running : ?, seconds_behind_masterislowor0, andnoerrorsinlast_errorerrelatedfields.3.useperperforced _schemakeriesinmysql5.7 fordetealedstatus
Sep 11, 2025 am 12:01 AM
MySQL ? ?? ??? ??? ETL ??? ?? ??
TobuildAnetlPullSfullsDataFrommultipleSources, transformSit ? loadlySittOmySql, followthesesteps : 1) mysql (AssourceortArget), API, csvfiles ? CSVFiles ? therotherDatabases.2) chooseAppropertooms/siClpropmon? WITHOPPOMPIC
Sep 10, 2025 am 06:53 AM
MySQL ?? ???? ??? ???? ??
??? ??? ?? ?? ??? ?? ? ?? ??? ?? ? ?? ????? ????? ???????. 1. ?? ? ?? ?? ? ????? ?????. 2. ??? ???? select ?? ?? ?????. 3. ??? ?? ?. 4. ???? ???? ?? ?? ??????. 5. ??? ?????. ? ???? ???? ??? ???????. ??? ???? ?? ???? ??????? ?????. ??? ?? ??? ?? ??? ???? ??? ?? ???? ??? ?? ??? ??????.
Sep 10, 2025 am 06:52 AM
MySQL?? ?? ?? ??? ??? ??????
?? ?? ???? ??? ???? ?? ? ? ????. ???? ?? ? 1 ? ? ?? ??? ???? CreateTableUsers (idintprimarykey, namevarchar (50))? ?? ?? ? ?? ?? ? ? ??? ??? ? ????. ?? ???? ?? AltertableUsersAddPrimaryKey (ID)? ????? ?? ???? ?? ?? ??????. ?? 1 ? ?? ?? ? ??? ?????. AltertableUsersDropPrimaryKey? ???? ?? ?? ??????.
Sep 10, 2025 am 06:50 AM
REGEXP? ?? MySQL?? ??? ? ???? ???? ??
MySQL? SQL ???? ?? ?? ??? ??? ???? ?? regexp ?? r ?? ???? ???? ?? ?? ??? ??? ?????. 1. regexp? ???? WHERE ??? ?? ???? ??? ? ????. ?? ??, SelectFromUserswhereEmailRegexp'gmail '? ??? ??? "gmail"? ?? ? ?? ?? ? ? ???, ?? ????? ??? ???? ????. 2. ???? ?? ??? ?????. (?? ??), ^ (???? ??), $ (???? ?), (0 ? ??? ??), (?? ??)? (0 ?? 1), [ABC] (?? ??), [A-Z] (?? ??
Sep 10, 2025 am 06:34 AM
MySQL ???? ??? ???? ??? ??????
MySQL? ??? ?? ??? ???? SQL ??? ???? ?? ???? ??????. 1. ?? ?? ??? ?????? - (?? ??) ?? #, ???? ? ???? ??? ?????. 2. ?? ?? ?? /.../? ???? ?? ??? ?? ?? ?????? ? ????? ??? ???? ? ??? ? ????. 3. ??? ??? ?? ?? /! 4. ??? ???? ??? ??? ?? ??? ?????, ????? ??? ???????, ??????? ???? ??? ???? ?? ??? ??? ??? SQL ????? ???? ????? ????.
Sep 10, 2025 am 05:20 AM
MySQL? ????? N ??? ?? ?? ?? ??
????? N-High ?? ???? Dense_Rank () ??? ???? ?? ????. 1. ?? ? ??? ?? : ?? ?? ?? ??? ????? ????? ???? ??? ??? ???? selectDistInct ? ?? Desclimit1offsetn-1; 2. DENSE_RANK () ?? : ?? ?? ???? ? ???? ??? ??? ??? ??????. ??? (? ?? ??, dense_rank () Over (Orderby Column Name Desc) ASRNKFR?? ??? ??? ??? ? ?????. 3. ?? ?? ?? : ?? MySQL8.0? ?????
Sep 10, 2025 am 04:18 AM
MySQL?? ??????? ???? ??? ??????
usedropdatabasedatabase_nametodeleteadatabaseinmysql; thispermanerally removesthedatabaseandallitscontentscontents.usedropdatabaseifexistsdatabase_nametoavoiderrorsifthedaBasedoesnotexist.thisActionisiirsirbersibersibiresdropivireges.alwaywayfifyfifyfifyfifyfifify
Sep 10, 2025 am 03:41 AM
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