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- TheDISTINCTkeywordinMySQLremovesduplicaterowsfromqueryresults,returningonlyuniquevaluesbasedontheselectedcolumns;itworksbytreatingrowsasduplicatesonlyifallselectedcolumnvaluesareidentical,includingNULLsasequal,andisappliedtosinglecolumnstoeliminatere
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- ???? ?? insertignoretoinsertarowonlyifitdoes? ???? ??, ??? skippingduplicatesbasedonauniqueconstraint; 2.useinsert ... onduplicatekeyupdateTupsert, insertingifnotexistsorupdatingifitdoes;
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