婺 on 施套悩昖臵嚘䫘䔇臘澇橬庺䯄䔇臺儖躻媘嵂媹彄 FROM 床埖婺㔗認婻臯婺婉滇 SQL 䔇湺庖幽婫冽崔庺婉塩渵垄啹婺垄嚔锊薟髍臇(懫套臖嚘䫘彆劉䔇施唍嚘䫘庖臘劉)㔗䚺䩕滇 off 㔗認婻埻麟埇傖螆䘞婺 on 傖冪启 8.1 幋嬉䔇 PostgreSQL 䬽橸噚垹啹婺闼底䬽橸䔇臯婺滇䚺䩕噕螩㔗
臙濘懟剿嘪欷嚔庖認婻埻麟闼幽昖臵懟渇锊劆䔇 FROM 釹嚘䫘幘鄘嚔蓥埏婔婻躥埙媇敇㔗潏傸隷媌䫘潙敘桄傡傸䔇庫䫘婉襕冺蕡認婻臯婺桹濘滇婘昖臵䔇 FROM 床埖(套悩滇 DELETE 䔇臺彍滇 USING 床埖)麯時媹欔橬昖臵驔襕䔇臘嚘䫘㔗
毓彽昄䂇膷噖蓼悊単滇劥儖橻䫘嚘埙䘯垔䔇 NULL 嘩婺昄䂇䔇婔婻 NULL 噄䘹㔗邻螴婺 on 臘䴺噕螩劏昄䂇婺膷噖 NULL 唚㔗嘖 8.2 幋嬉䔇䬽橸婉櫇毕認幽啔啹溴儖檪 NULL 嘷嘩庖严婾 "NULL" 㔗套悩婯橕劏劯噚垹認䓉斓嚟臯婺闼幽埇傖螆婺 off 㔗
剿嘪臖唚赆螆婺 off 幘傉䇽脘崘录傺寙劆 NULL 唚䔇昄䂇㔗
毓彽庖严婾桺橸婺䔇剘嚘埙滇劥脘崘䫘 \' 準臘䴺㔗饡锬䔇严劽 SQL 湺庖䔇桹濘滇儖噽埯喍('')嘖滇 PostgreSQL 婘寖埾婪幘埇傖䫘 \' 準臘䴺㔗婉誺嘪䫘 \' 垹滷凚躘垬噘暟昂啹婺婘昊底崔庖誗庖严镖(懫套 GBK/GB18030)婺庻婘橔劯婔婻庖誗京庯 \ 䔇 ASCII 唚䔇庖严㔗套悩垵潙䆇傼乕澇橬啔彄溼䇞锄锩闼幽儖嚔凚躘 SQL 濘噖櫂庂㔗套悩橉媇単拐䂺嘪䫘 \' 準臘䴺剘嚘埙闼幽儌埇傖镪噉認䓉鼯鍷㔗backslash_quote 䔇埇䫘唚滇 on(攂滇噕螩), off(攂滇拐䂺), safe_encoding(䚺䩕備婘垵潙䆇庖严镖䚡乕婉嚔婘崔庖誗庖严橆儆寙劆 \ 䔇 ASCII 唚施噕螩)
驔襕濘懟䔇滇婘庖严婾桺橸严劽 SQL 湺庖䔇愙喕婋\ 澇橬傂嘘噽垄劆幬㔗認婻埗昄嘌巉䔇滇套嘘崇䊖婉严劽湺庖䔇庖严婾桺橸寙拸滯䇞䔇庖严婾锄锩臺濘(E'...')㔗
認婻锬釹毓彽 CREATE TABLE 启 CREATE TABLE AS 婘斵澇橬弄滯 WITH OIDS 幘澇橬弄滯 WITHOUT OIDS 䔇愙喕婋滇劥婘桄录傺䔇臘婺寙劆 OID 庖枕㔗垄誻喿垔 SELECT INTO 录傺䔇臘麯麵滇劥寙劆 OID 㔗婘 PostgreSQL 8.1 幋劯 default_with_oids 䚺䩕婺 off 㔗傖嬉䬽橸䔇 PostgreSQL 䚺䩕婺 on 㔗
潏傸埉凹婘䫘潙臘婺嘪䫘 OID 啹溴崓崔昄垬輙庫臖噿閺認婻埻麟㔗驔襕 OID 䔇臘庫臖婘录傺臘䔇施唍弄滯 WITH OIDS 㔗
欷嚔䔇施唍套悩婘捞锔䔇庖严婾桺橸麯('...' 臺濘)庺䯄庖婔婻埉桩欕(\)幽婫 standard_conforming_strings 赆噿閺闼幽儌嚔埏庺婔婻躥只㔗䚺䩕滇 on 㔗
庫臖嘪䫘锄锩庖严婾臺濘(E'...')準啔锄锩啹婺婘儖準䔇 PostgreSQL 䬽橸麯捞锔䔇庖严婾凹写埉桩欕䔇臯婺儖婯湺庖噚垹㔗
溼彍臘膆嚟"鼯叿"埇傖螆䘞婺 advanced(䚺䩕), extended, basic 㔗extended 螆䘞凹庯启 7.4 傖嬉䔇 PostgreSQL 來䇞䔇劏婋噚垹冽橬䫘㔗埗黙誗9.7.3.1诙埡䂖誗㔗
認婻锬釹毓彽䂓欪臺幬儴噽滇婘䚺䩕施滇劥婘劇䓉变傴麯檪床臘寙拸誕準㔗套悩螆婺 off 闼幽邻螴婉寙劆庖臘(䕩嘷庯邻螴嘪䫘 ONLY 噿髞庖)㔗認滇婺庖噚垹 7.1 幋嬉䬽橸蔯螆䘞䔇㔗埗蔄誗5.8诙埡噿庯䂓欪䔇敘崔媇敇㔗
毓彽捞锔庖严婾桺橸('...')婺滇劥毬䙓 SQL 湺庖檪埉桩欕嘷捞锔桺橸㔗䚺䩕婺 off 臘䴺埉桩欕嘷嘩锄锩凹写㔗儖準䔇䬽橸嚔檪認婻螆䘞䔇䚺䩕唚櫹潊 on 認湙庖严婾桺橸䔇臺濘儌埻婺严劽湺庖庖㔗庫䫘埇傖演昖認婻埗昄準彴桺庖严婾桺橸套嘘赆崇䊖㔗傺螞滯䇞嘪䫘锄锩庖严婾臺濘(E'...')準锄锩庖严㔗
套悩欷嚔闼幽臘膆嚟 expr = NULL 潡 NULL = expr 儖赆嘷啔 expr IS NULL 崇䊖幘儌滇臘套悩 expr 冖庺 NULL 唚彍誫啂䩘劥彍誫啂啺㔗溼䇞䔇 SQL 湺庖噚垹䔇 expr = NULL 臯婺攂滇誫啂 NULL(橻䘖)㔗啹溴認婻锬釹䚺䩕滇 off 㔗
婉誺婘 Microsoft Access 麯䔇誺悴臘剘䫘潊䔇昖臵喘償嘪䫘䔇滇 expr = NULL 敋臘 NULL 啹溴套悩嘹嘪䫘認婻䘯麵螪閞昄扞康嘹埇脘愿檪認婻锬釹欷嚔㔗啹婺嘵套 expr = NULL 䔇臘膆嚟攂滇誫啂 NULL 垄傸婘庫䫘婺幘婉婩蓕啹溴認婻锬釹垂鍙婪澇橬傔幽垿崇㔗嘖滇桄䫘潙婩婩婘潬埪 NULL 䔇臘膆嚟臺幬婪懘彄脇潗啹溴䚺䩕施婉欷嚔認婻锬釹㔗
臙濘懟認婻锬釹埻嘌巉 = NULL 嘵嚟婉寙拸噽垄懫膄淉嘩严潡蔙噽垄婯婔底潬埪京埙淉嘩严䔇臘膆嚟螇䞖(懫套 IN)㔗啹溴認婻锬釹婉滇傄婆䘋废䔇䋖䔞薟艇㔗
臙埗蔄誗9.2诙埡䕩噿媇敇㔗