{"id":9867,"date":"2017-03-30T05:36:56","date_gmt":"2017-03-30T03:36:56","guid":{"rendered":"https:\/\/www.dbi-services.com\/blog\/can-i-do-it-with-postgresql-11-nls_date_format\/"},"modified":"2017-03-30T05:36:56","modified_gmt":"2017-03-30T03:36:56","slug":"can-i-do-it-with-postgresql-11-nls_date_format","status":"publish","type":"post","link":"https:\/\/www.dbi-services.com\/blog\/can-i-do-it-with-postgresql-11-nls_date_format\/","title":{"rendered":"Can I do it with PostgreSQL? \u2013 11 \u2013 NLS_DATE_FORMAT"},"content":{"rendered":"

Following the last post about time zones<\/a> this post is about the display and default format of date and time values. What people usually do to get a consistent display of date and time values in Oracle is to set NLS_DATE_FORMAT<\/a>:<\/p>\n

\nSQL> show parameter nls_date_format;\n\nNAME\t\t\t\t     TYPE\t VALUE\n------------------------------------ ----------- ------------------------------\nnls_date_format \t\t     string\t YYYY-MON-DD HH24:MI:SS\n\nSQL> alter session set nls_date_format='DD.MM.YYYY HH24:MI:SS';\n\nSession altered.\n\nSQL> select sysdate from dual;\n\nSYSDATE\n-------------------\n29.03.2017 16:26:11\n\nSQL> alter session set nls_date_format='YYYY-MON-DD HH24:MI:SS';\n\nSession altered.\n\nSQL> select sysdate from dual;\n\nSYSDATE\n--------------------\n2017-MAR-29 16:31:01\n<\/pre>\n
Obviously PostgreSQL does not know anything about NLS_DATE_FORMAT, so what does it provide for doing the same? <\/p>\n
<\/p>\n
First of all (and this is true for Oracle as well as for PostgreSQL) this is all about displaying date and time values and interpreting strings that shall be converted to date and time values. This has nothing to do with the internal storage.<\/p>\n
What controls the display of date and time specific values in PostgreSQL is the parameter datestyle<\/a>, the default is ISO<\/a>:<\/p>\n
\npostgres=# show datestyle;\n DateStyle \n-----------\n ISO, MDY\n(1 row)\n<\/pre>\n
MDY here represents: MONTH-DAY-YEAR. If you want to change this on the session level you can:<\/p>\n
\npostgres=# set datestyle='SQL, MDY';\nSET\npostgres=# select now();\n              now               \n--------------------------------\n 03\/29\/2017 18:13:15.475693 GMT\n(1 row)\n<\/pre>\n
You can do the same by setting the PGDATESTYLE<\/a> environment variable before starting a new connection:<\/p>\n
\npostgres@pgbox:\/home\/postgres\/ [PG962] export PGDATESTYLE='SQL, MDY'\npostgres@pgbox:\/home\/postgres\/ [PG962] psql postgres\npsql (9.6.2 dbi services build)\nType \"help\" for help.\n\npostgres=# select now();\n              now               \n--------------------------------\n 03\/29\/2017 18:15:29.765396 GMT\n(1 row)\n<\/pre>\n
When you have a string and you want to insert that string into a column which is defined as date, how can you do this? PostgreSQL is very flexible here:<\/p>\n
\npostgres=# create table t1 ( a date );\nCREATE TABLE\npostgres=# insert into t1 (a) values ('2017.01.01');\nINSERT 0 1\npostgres=# insert into t1 (a) values ('2017-01-01');\nINSERT 0 1\npostgres=# insert into t1 (a) values ('2017-JAN-01');\nINSERT 0 1\npostgres=# insert into t1 (a) values ('2017-JAN-01 11:11:11');\nINSERT 0 1\npostgres=# insert into t1 (a) values ('2017\/01\/01 11:11:11');\nINSERT 0 1\npostgres=# insert into t1 (a) values ('20170101 111111');\nINSERT 0 1\n<\/pre>\n
All these work without specifying a format mask as you would need to do it in Oracle. The rules how a string is interpreted are documented here<\/a>. <\/p>\n
When you want to convert a string into a date or timestamp you can use one of the make_* functions<\/a>:<\/p>\n
\npostgres=# select make_date(2017,01,01);\n make_date  \n------------\n 2017-01-01\n(1 row)\npostgres=# select make_timestamp (2017,01,01,00,00,00);\n   make_timestamp    \n---------------------\n 2017-01-01 00:00:00\n(1 row)\n<\/pre>\n
… or use the data type formatting functions<\/a>:<\/p>\n
\npostgres=# select to_date('2017.01.01','YYYY.MM.DD');\n  to_date   \n------------\n 2017-01-01\n(1 row)\n\npostgres=# select to_date('2017-JAN-01','YYYY.Mon.DD');\n  to_date   \n------------\n 2017-01-01\n(1 row)\n<\/pre>\n
Hope this helps …<\/p>\n","protected":false},"excerpt":{"rendered":"
Following the last post about time zones this post is about the display and default format of date and time values. What people usually do to get a consistent display of date and time values in Oracle is to set NLS_DATE_FORMAT: SQL> show parameter nls_date_format; NAME TYPE VALUE ———————————— ———– —————————— nls_date_format string YYYY-MON-DD HH24:MI:SS […]<\/p>\n","protected":false},"author":29,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[229],"tags":[77],"type_dbi":[],"class_list":["post-9867","post","type-post","status-publish","format-standard","hentry","category-database-administration-monitoring","tag-postgresql"],"acf":[],"yoast_head":"\nCan I do it with PostgreSQL? \u2013 11 \u2013 NLS_DATE_FORMAT - dbi Blog<\/title>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/www.dbi-services.com\/blog\/can-i-do-it-with-postgresql-11-nls_date_format\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"Can I do it with PostgreSQL? \u2013 11 \u2013 NLS_DATE_FORMAT\" \/>\n<meta property=\"og:description\" content=\"Following the last post about time zones this post is about the display and default format of date and time values. What people usually do to get a consistent display of date and time values in Oracle is to set NLS_DATE_FORMAT: SQL> show parameter nls_date_format; NAME TYPE VALUE ------------------------------------ ----------- ------------------------------ nls_date_format string YYYY-MON-DD HH24:MI:SS […]\" \/>\n<meta property=\"og:url\" content=\"https:\/\/www.dbi-services.com\/blog\/can-i-do-it-with-postgresql-11-nls_date_format\/\" \/>\n<meta property=\"og:site_name\" content=\"dbi Blog\" \/>\n<meta property=\"article:published_time\" content=\"2017-03-30T03:36:56+00:00\" \/>\n<meta name=\"author\" content=\"Daniel Westermann\" \/>\n<meta name=\"twitter:card\" content=\"summary_large_image\" \/>\n<meta name=\"twitter:creator\" content=\"@westermanndanie\" \/>\n<meta name=\"twitter:label1\" content=\"Written by\" \/>\n\t<meta name=\"twitter:data1\" content=\"Daniel Westermann\" \/>\n\t<meta name=\"twitter:label2\" content=\"Est. reading time\" \/>\n\t<meta name=\"twitter:data2\" content=\"2 minutes\" \/>\n<script type=\"application\/ld+json\" class=\"yoast-schema-graph\">{\"@context\":\"https:\/\/schema.org\",\"@graph\":[{\"@type\":\"Article\",\"@id\":\"https:\/\/www.dbi-services.com\/blog\/can-i-do-it-with-postgresql-11-nls_date_format\/#article\",\"isPartOf\":{\"@id\":\"https:\/\/www.dbi-services.com\/blog\/can-i-do-it-with-postgresql-11-nls_date_format\/\"},\"author\":{\"name\":\"Daniel Westermann\",\"@id\":\"https:\/\/www.dbi-services.com\/blog\/#\/schema\/person\/8d08e9bd996a89bd75c0286cbabf3c66\"},\"headline\":\"Can I do it with PostgreSQL? \u2013 11 \u2013 NLS_DATE_FORMAT\",\"datePublished\":\"2017-03-30T03:36:56+00:00\",\"mainEntityOfPage\":{\"@id\":\"https:\/\/www.dbi-services.com\/blog\/can-i-do-it-with-postgresql-11-nls_date_format\/\"},\"wordCount\":254,\"commentCount\":0,\"keywords\":[\"PostgreSQL\"],\"articleSection\":[\"Database Administration & Monitoring\"],\"inLanguage\":\"en-US\",\"potentialAction\":[{\"@type\":\"CommentAction\",\"name\":\"Comment\",\"target\":[\"https:\/\/www.dbi-services.com\/blog\/can-i-do-it-with-postgresql-11-nls_date_format\/#respond\"]}]},{\"@type\":\"WebPage\",\"@id\":\"https:\/\/www.dbi-services.com\/blog\/can-i-do-it-with-postgresql-11-nls_date_format\/\",\"url\":\"https:\/\/www.dbi-services.com\/blog\/can-i-do-it-with-postgresql-11-nls_date_format\/\",\"name\":\"Can I do it with PostgreSQL? \u2013 11 \u2013 NLS_DATE_FORMAT - dbi Blog\",\"isPartOf\":{\"@id\":\"https:\/\/www.dbi-services.com\/blog\/#website\"},\"datePublished\":\"2017-03-30T03:36:56+00:00\",\"author\":{\"@id\":\"https:\/\/www.dbi-services.com\/blog\/#\/schema\/person\/8d08e9bd996a89bd75c0286cbabf3c66\"},\"breadcrumb\":{\"@id\":\"https:\/\/www.dbi-services.com\/blog\/can-i-do-it-with-postgresql-11-nls_date_format\/#breadcrumb\"},\"inLanguage\":\"en-US\",\"potentialAction\":[{\"@type\":\"ReadAction\",\"target\":[\"https:\/\/www.dbi-services.com\/blog\/can-i-do-it-with-postgresql-11-nls_date_format\/\"]}]},{\"@type\":\"BreadcrumbList\",\"@id\":\"https:\/\/www.dbi-services.com\/blog\/can-i-do-it-with-postgresql-11-nls_date_format\/#breadcrumb\",\"itemListElement\":[{\"@type\":\"ListItem\",\"position\":1,\"name\":\"Accueil\",\"item\":\"https:\/\/www.dbi-services.com\/blog\/\"},{\"@type\":\"ListItem\",\"position\":2,\"name\":\"Can I do it with PostgreSQL? \u2013 11 \u2013 NLS_DATE_FORMAT\"}]},{\"@type\":\"WebSite\",\"@id\":\"https:\/\/www.dbi-services.com\/blog\/#website\",\"url\":\"https:\/\/www.dbi-services.com\/blog\/\",\"name\":\"dbi Blog\",\"description\":\"\",\"potentialAction\":[{\"@type\":\"SearchAction\",\"target\":{\"@type\":\"EntryPoint\",\"urlTemplate\":\"https:\/\/www.dbi-services.com\/blog\/?s={search_term_string}\"},\"query-input\":{\"@type\":\"PropertyValueSpecification\",\"valueRequired\":true,\"valueName\":\"search_term_string\"}}],\"inLanguage\":\"en-US\"},{\"@type\":\"Person\",\"@id\":\"https:\/\/www.dbi-services.com\/blog\/#\/schema\/person\/8d08e9bd996a89bd75c0286cbabf3c66\",\"name\":\"Daniel Westermann\",\"image\":{\"@type\":\"ImageObject\",\"inLanguage\":\"en-US\",\"@id\":\"https:\/\/secure.gravatar.com\/avatar\/31350ceeecb1dd8986339a29bf040d4cd3cd087d410deccd8f55234466d6c317?s=96&d=mm&r=g\",\"url\":\"https:\/\/secure.gravatar.com\/avatar\/31350ceeecb1dd8986339a29bf040d4cd3cd087d410deccd8f55234466d6c317?s=96&d=mm&r=g\",\"contentUrl\":\"https:\/\/secure.gravatar.com\/avatar\/31350ceeecb1dd8986339a29bf040d4cd3cd087d410deccd8f55234466d6c317?s=96&d=mm&r=g\",\"caption\":\"Daniel Westermann\"},\"description\":\"Daniel Westermann is Principal Consultant and Technology Leader Open Infrastructure at dbi services. He has more than 15 years of experience in management, engineering and optimization of databases and infrastructures, especially on Oracle and PostgreSQL. Since the beginning of his career, he has specialized in Oracle Technologies and is Oracle Certified Professional 12c and Oracle Certified Expert RAC\/GridInfra. Over time, Daniel has become increasingly interested in open source technologies, becoming \u201cTechnology Leader Open Infrastructure\u201d and PostgreSQL expert. \u00a0Based on community or EnterpriseDB tools, he develops and installs complex high available solutions with PostgreSQL. He is also a certified PostgreSQL Plus 9.0 Professional and a Postgres Advanced Server 9.4 Professional. He is a regular speaker at PostgreSQL conferences in Switzerland and Europe. Today Daniel is also supporting our customers on AWS services such as AWS RDS, database migrations into the cloud, EC2 and automated infrastructure management with AWS SSM (System Manager). He is a certified AWS Solutions Architect Professional. Prior to dbi services, Daniel was Management System Engineer at LC SYSTEMS-Engineering AG in Basel. Before that, he worked as Oracle Developper &\u00a0Project Manager at Delta Energy Solutions AG in Basel (today Powel AG). Daniel holds a diploma in Business Informatics (DHBW, Germany). His branch-related experience mainly covers the pharma industry, the financial sector, energy, lottery and telecommunications.\",\"sameAs\":[\"https:\/\/x.com\/westermanndanie\"],\"url\":\"https:\/\/www.dbi-services.com\/blog\/author\/daniel-westermann\/\"}]}<\/script>\n<!-- \/ Yoast SEO Premium plugin. -->","yoast_head_json":{"title":"Can I do it with PostgreSQL? \u2013 11 \u2013 NLS_DATE_FORMAT - dbi Blog","robots":{"index":"index","follow":"follow","max-snippet":"max-snippet:-1","max-image-preview":"max-image-preview:large","max-video-preview":"max-video-preview:-1"},"canonical":"https:\/\/www.dbi-services.com\/blog\/can-i-do-it-with-postgresql-11-nls_date_format\/","og_locale":"en_US","og_type":"article","og_title":"Can I do it with PostgreSQL? \u2013 11 \u2013 NLS_DATE_FORMAT","og_description":"Following the last post about time zones this post is about the display and default format of date and time values. What people usually do to get a consistent display of date and time values in Oracle is to set NLS_DATE_FORMAT: SQL> show parameter nls_date_format; NAME TYPE VALUE ------------------------------------ ----------- ------------------------------ nls_date_format string YYYY-MON-DD HH24:MI:SS […]","og_url":"https:\/\/www.dbi-services.com\/blog\/can-i-do-it-with-postgresql-11-nls_date_format\/","og_site_name":"dbi Blog","article_published_time":"2017-03-30T03:36:56+00:00","author":"Daniel Westermann","twitter_card":"summary_large_image","twitter_creator":"@westermanndanie","twitter_misc":{"Written by":"Daniel Westermann","Est. reading time":"2 minutes"},"schema":{"@context":"https:\/\/schema.org","@graph":[{"@type":"Article","@id":"https:\/\/www.dbi-services.com\/blog\/can-i-do-it-with-postgresql-11-nls_date_format\/#article","isPartOf":{"@id":"https:\/\/www.dbi-services.com\/blog\/can-i-do-it-with-postgresql-11-nls_date_format\/"},"author":{"name":"Daniel Westermann","@id":"https:\/\/www.dbi-services.com\/blog\/#\/schema\/person\/8d08e9bd996a89bd75c0286cbabf3c66"},"headline":"Can I do it with PostgreSQL? \u2013 11 \u2013 NLS_DATE_FORMAT","datePublished":"2017-03-30T03:36:56+00:00","mainEntityOfPage":{"@id":"https:\/\/www.dbi-services.com\/blog\/can-i-do-it-with-postgresql-11-nls_date_format\/"},"wordCount":254,"commentCount":0,"keywords":["PostgreSQL"],"articleSection":["Database Administration & Monitoring"],"inLanguage":"en-US","potentialAction":[{"@type":"CommentAction","name":"Comment","target":["https:\/\/www.dbi-services.com\/blog\/can-i-do-it-with-postgresql-11-nls_date_format\/#respond"]}]},{"@type":"WebPage","@id":"https:\/\/www.dbi-services.com\/blog\/can-i-do-it-with-postgresql-11-nls_date_format\/","url":"https:\/\/www.dbi-services.com\/blog\/can-i-do-it-with-postgresql-11-nls_date_format\/","name":"Can I do it with PostgreSQL? \u2013 11 \u2013 NLS_DATE_FORMAT - dbi Blog","isPartOf":{"@id":"https:\/\/www.dbi-services.com\/blog\/#website"},"datePublished":"2017-03-30T03:36:56+00:00","author":{"@id":"https:\/\/www.dbi-services.com\/blog\/#\/schema\/person\/8d08e9bd996a89bd75c0286cbabf3c66"},"breadcrumb":{"@id":"https:\/\/www.dbi-services.com\/blog\/can-i-do-it-with-postgresql-11-nls_date_format\/#breadcrumb"},"inLanguage":"en-US","potentialAction":[{"@type":"ReadAction","target":["https:\/\/www.dbi-services.com\/blog\/can-i-do-it-with-postgresql-11-nls_date_format\/"]}]},{"@type":"BreadcrumbList","@id":"https:\/\/www.dbi-services.com\/blog\/can-i-do-it-with-postgresql-11-nls_date_format\/#breadcrumb","itemListElement":[{"@type":"ListItem","position":1,"name":"Accueil","item":"https:\/\/www.dbi-services.com\/blog\/"},{"@type":"ListItem","position":2,"name":"Can I do it with PostgreSQL? \u2013 11 \u2013 NLS_DATE_FORMAT"}]},{"@type":"WebSite","@id":"https:\/\/www.dbi-services.com\/blog\/#website","url":"https:\/\/www.dbi-services.com\/blog\/","name":"dbi Blog","description":"","potentialAction":[{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https:\/\/www.dbi-services.com\/blog\/?s={search_term_string}"},"query-input":{"@type":"PropertyValueSpecification","valueRequired":true,"valueName":"search_term_string"}}],"inLanguage":"en-US"},{"@type":"Person","@id":"https:\/\/www.dbi-services.com\/blog\/#\/schema\/person\/8d08e9bd996a89bd75c0286cbabf3c66","name":"Daniel Westermann","image":{"@type":"ImageObject","inLanguage":"en-US","@id":"https:\/\/secure.gravatar.com\/avatar\/31350ceeecb1dd8986339a29bf040d4cd3cd087d410deccd8f55234466d6c317?s=96&d=mm&r=g","url":"https:\/\/secure.gravatar.com\/avatar\/31350ceeecb1dd8986339a29bf040d4cd3cd087d410deccd8f55234466d6c317?s=96&d=mm&r=g","contentUrl":"https:\/\/secure.gravatar.com\/avatar\/31350ceeecb1dd8986339a29bf040d4cd3cd087d410deccd8f55234466d6c317?s=96&d=mm&r=g","caption":"Daniel Westermann"},"description":"Daniel Westermann is Principal Consultant and Technology Leader Open Infrastructure at dbi services. He has more than 15 years of experience in management, engineering and optimization of databases and infrastructures, especially on Oracle and PostgreSQL. Since the beginning of his career, he has specialized in Oracle Technologies and is Oracle Certified Professional 12c and Oracle Certified Expert RAC\/GridInfra. Over time, Daniel has become increasingly interested in open source technologies, becoming \u201cTechnology Leader Open Infrastructure\u201d and PostgreSQL expert. \u00a0Based on community or EnterpriseDB tools, he develops and installs complex high available solutions with PostgreSQL. He is also a certified PostgreSQL Plus 9.0 Professional and a Postgres Advanced Server 9.4 Professional. He is a regular speaker at PostgreSQL conferences in Switzerland and Europe. Today Daniel is also supporting our customers on AWS services such as AWS RDS, database migrations into the cloud, EC2 and automated infrastructure management with AWS SSM (System Manager). He is a certified AWS Solutions Architect Professional. Prior to dbi services, Daniel was Management System Engineer at LC SYSTEMS-Engineering AG in Basel. Before that, he worked as Oracle Developper &\u00a0Project Manager at Delta Energy Solutions AG in Basel (today Powel AG). Daniel holds a diploma in Business Informatics (DHBW, Germany). His branch-related experience mainly covers the pharma industry, the financial sector, energy, lottery and telecommunications.","sameAs":["https:\/\/x.com\/westermanndanie"],"url":"https:\/\/www.dbi-services.com\/blog\/author\/daniel-westermann\/"}]}},"_links":{"self":[{"href":"https:\/\/www.dbi-services.com\/blog\/wp-json\/wp\/v2\/posts\/9867","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.dbi-services.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.dbi-services.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.dbi-services.com\/blog\/wp-json\/wp\/v2\/users\/29"}],"replies":[{"embeddable":true,"href":"https:\/\/www.dbi-services.com\/blog\/wp-json\/wp\/v2\/comments?post=9867"}],"version-history":[{"count":0,"href":"https:\/\/www.dbi-services.com\/blog\/wp-json\/wp\/v2\/posts\/9867\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.dbi-services.com\/blog\/wp-json\/wp\/v2\/media?parent=9867"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.dbi-services.com\/blog\/wp-json\/wp\/v2\/categories?post=9867"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.dbi-services.com\/blog\/wp-json\/wp\/v2\/tags?post=9867"},{"taxonomy":"type","embeddable":true,"href":"https:\/\/www.dbi-services.com\/blog\/wp-json\/wp\/v2\/type_dbi?post=9867"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}