{"id":130458,"date":"2022-04-13T18:00:11","date_gmt":"2022-04-13T22:00:11","guid":{"rendered":"https:\/\/brainstation.io\/?post_type=codex-reference&#038;p=130458"},"modified":"2025-02-04T14:38:54","modified_gmt":"2025-02-04T19:38:54","slug":"union","status":"publish","type":"codex-reference","link":"https:\/\/brainstation.io\/learn\/sql\/union","title":{"rendered":"Union"},"content":{"rendered":"\n<header class=\"wp-block-bstn-blocks-hero-simple bstn-blocks-hero-simple\"><div class=\"bstn-blocks-hero-simple__full-width-wrapper bstn-blocks-hero-simple__full-width-wrapper--main bstn-blocks-hero-simple__full-width-wrapper--bg-flair\"><svg xmlns=\"http:\/\/www.w3.org\/2000\/svg\" viewbox=\"0 0 1140 621\" fill=\"none\" class=\"bstn-blocks-hero-simple__bg-flair--rich\"><g opacity=\"0.55\"><path stroke=\"#3C4556\" strokelinecap=\"square\" d=\"M60.026 736.434V203.02\"><\/path><path stroke=\"#3C4556\" strokelinecap=\"square\" d=\"M60.364 436.132L-120 436.131l180.364.001zm0-99.873H-120 60.364zm0-99.872H-120 60.364zM128 536.004h-248 248z\" cliprule=\"evenodd\"><\/path><path fill=\"#3C4556\" fillrule=\"evenodd\" d=\"M57.518 535.982a2.286 2.286 0 114.572 0 2.286 2.286 0 01-4.572 0zm0-99.836a2.286 2.286 0 114.572-.002 2.286 2.286 0 01-4.572.002zm0-99.837a2.286 2.286 0 114.572-.002 2.286 2.286 0 01-4.572.002zm0-99.837a2.286 2.286 0 114.572-.002 2.286 2.286 0 01-4.572.002z\" cliprule=\"evenodd\"><\/path><\/g><g opacity=\"0.55\"><path stroke=\"#3C4556\" strokelinecap=\"square\" d=\"M979.195-28.206V397.98m81.185-524.745V397.98\"><\/path><path stroke=\"#3C4556\" strokelinecap=\"square\" d=\"M1141.45 168.46H964h177.45zm0 98.334H964h177.45zm0 98.333H964h177.45zm66.55-295H964h244z\" cliprule=\"evenodd\"><\/path><path fill=\"#3C4556\" fillrule=\"evenodd\" d=\"M1138.66 70.148a2.244 2.244 0 104.49 0 2.246 2.246 0 10-4.49-.001zm-80.21 0c0 1.243 1.01 2.251 2.25 2.251s2.25-1.008 2.25-2.251c0-1.243-1.01-2.251-2.25-2.251s-2.25 1.008-2.25 2.25zm-81.707 0a2.25 2.25 0 104.5.004 2.25 2.25 0 00-4.5-.005zm81.707 98.299a2.252 2.252 0 002.25 2.251 2.252 2.252 0 000-4.503 2.253 2.253 0 00-2.25 2.252zm-81.707 0a2.25 2.25 0 104.498 0 2.25 2.25 0 00-2.249-2.252 2.25 2.25 0 00-2.249 2.252zm161.917-.001a2.244 2.244 0 104.49 0 2.246 2.246 0 10-4.49 0zm0 98.299a2.244 2.244 0 104.49 0 2.246 2.246 0 10-4.49 0zm-80.21 0c0 1.243 1.01 2.251 2.25 2.251s2.25-1.008 2.25-2.251c0-1.243-1.01-2.251-2.25-2.251s-2.25 1.008-2.25 2.251zm-81.707 0a2.25 2.25 0 104.5.002 2.25 2.25 0 00-4.5-.002zm81.707 98.299c0 1.243 1.01 2.251 2.25 2.251s2.25-1.008 2.25-2.251c0-1.243-1.01-2.251-2.25-2.251s-2.25 1.008-2.25 2.251zm-81.707 0a2.25 2.25 0 104.5.002 2.25 2.25 0 00-4.5-.002zm161.917 0a2.244 2.244 0 104.49 0 2.246 2.246 0 10-4.49 0z\" cliprule=\"evenodd\"><\/path><\/g><\/svg><div class=\"bstn-blocks-hero-simple__container\"><div class=\"bstn-blocks-hero-simple__copy-container\"><div class=\"bstn-blocks-hero-simple__subtitle-wrapper\"><p class=\"bstn-blocks-hero-simple__subtitle\">SQL tutorial<\/p><\/div><h1 class=\"bstn-blocks-hero-simple__title\">SQL Union<\/h1><p class=\"bstn-blocks-hero-simple__description\"><meta charset=\"utf-8\">Learn more about SQL, a standard language for interacting with databases and storing, manipulating, and retrieving data from databases.<br><br><a rel=\"noreferrer noopener\" href=\"https:\/\/brainstation.io\/learn\/sql\/\" target=\"_blank\">Go hands-on with SQL in our free interactive SQL tutorial.<\/a><\/p><\/div><div class=\"bstn-blocks-hero-simple__image-container\"><\/div><\/div><\/div><\/header>\n\n\n\n<div class=\"wp-block-columns is-layout-flex wp-container-core-columns-is-layout-1 wp-block-columns-is-layout-flex\">\n<div class=\"wp-block-column is-layout-flow wp-block-column-is-layout-flow\" style=\"flex-basis:66.66%\">\n<p class=\"is-style-bstn-paragraph-documentation-body\">The SQL <code>UNION<\/code> clause can be used to concatenate the results of multiple <code>SELECT<\/code> statements together into a single result.<\/p>\n\n\n\n<p class=\"is-style-bstn-paragraph-documentation-body\">In the general form, it is used as linkage between two or more <code>SELECT<\/code> statements as below:<\/p>\n\n\n\n<div class=\"wp-block-bstn-blocks-code-snippet bstn-blocks-code-snippet\" data-code-snippet=\"true\"><div class=\"bstn-blocks-code-snippet__title-bar\"><span class=\"bstn-blocks-code-snippet__title\">Code Example<\/span><button class=\"bstn-blocks-code-snippet__copy-trigger\" data-copy-to-clipboard=\"true\"><svg viewbox=\"0 0 12 13\" fill=\"none\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\" class=\"bstn-blocks-code-snippet__copy-trigger-icon\"><path d=\"M10.875.5h-7.5c-.633 0-1.125.516-1.125 1.125V2.75H1.125C.492 2.75 0 3.266 0 3.875v7.5A1.11 1.11 0 001.125 12.5h7.5c.61 0 1.125-.492 1.125-1.125V10.25h1.125c.61 0 1.125-.492 1.125-1.125v-7.5A1.14 1.14 0 0010.875.5zm-2.39 10.875h-7.22c-.093 0-.14-.047-.14-.14v-7.22c0-.07.047-.14.14-.14h.985v5.25a1.11 1.11 0 001.125 1.125h5.25v.984c0 .094-.07.141-.14.141zm2.25-2.25h-7.22c-.093 0-.14-.047-.14-.14v-7.22c0-.07.047-.14.14-.14h7.22c.07 0 .14.07.14.14v7.22c0 .093-.07.14-.14.14z\" fill=\"currentColor\"><\/path><\/svg><span data-copy-to-clipboard-text=\"true\">Copy<\/span><\/button><\/div><pre class=\"bstn-blocks-code-snippet__code-snippet-area match-braces line-numbers language-sql\" data-language=\"sql\"><code>SELECT \u2026 FROM \u2026  \nUNION\nSELECT \u2026 FROM \u2026  \nUNION\nSELECT \u2026 FROM \u2026  \n\u2026\n<\/code><\/pre><\/div>\n\n\n\n<p class=\"is-style-bstn-paragraph-documentation-body\">Since the results are being concatenated, it is a requirement that the schema (number of columns and data types) in the results of the individual queries match, otherwise the results will not be able to be concatenated.<\/p>\n\n\n\n<p class=\"is-style-bstn-paragraph-documentation-body\">For example, we can put together the results of two simple <code>SELECT<\/code> statements from the employees table using <code>USING<\/code>, to find employees who have first names either \u201cGeorgi\u201d or \u201cAnnelise\u201d:<\/p>\n\n\n\n<div class=\"wp-block-bstn-blocks-code-snippet bstn-blocks-code-snippet\" data-code-snippet=\"true\"><div class=\"bstn-blocks-code-snippet__title-bar\"><span class=\"bstn-blocks-code-snippet__title\">Code Example<\/span><button class=\"bstn-blocks-code-snippet__copy-trigger\" data-copy-to-clipboard=\"true\"><svg viewbox=\"0 0 12 13\" fill=\"none\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\" class=\"bstn-blocks-code-snippet__copy-trigger-icon\"><path d=\"M10.875.5h-7.5c-.633 0-1.125.516-1.125 1.125V2.75H1.125C.492 2.75 0 3.266 0 3.875v7.5A1.11 1.11 0 001.125 12.5h7.5c.61 0 1.125-.492 1.125-1.125V10.25h1.125c.61 0 1.125-.492 1.125-1.125v-7.5A1.14 1.14 0 0010.875.5zm-2.39 10.875h-7.22c-.093 0-.14-.047-.14-.14v-7.22c0-.07.047-.14.14-.14h.985v5.25a1.11 1.11 0 001.125 1.125h5.25v.984c0 .094-.07.141-.14.141zm2.25-2.25h-7.22c-.093 0-.14-.047-.14-.14v-7.22c0-.07.047-.14.14-.14h7.22c.07 0 .14.07.14.14v7.22c0 .093-.07.14-.14.14z\" fill=\"currentColor\"><\/path><\/svg><span data-copy-to-clipboard-text=\"true\">Copy<\/span><\/button><\/div><pre class=\"bstn-blocks-code-snippet__code-snippet-area match-braces line-numbers language-sql\" data-language=\"sql\"><code>SELECT * FROM employees WHERE first_name = \"Georgi\"\nUNION\nSELECT * FROM employees WHERE first_name = \"Anneke\";\n<\/code><\/pre><\/div>\n\n\n\n<p class=\"is-style-bstn-paragraph-documentation-body\">For this simple example, it should be noted that an equivalent result can be achieved using a <code>WHERE<\/code> clause and <code>OR<\/code> with the two predicates, or using <code>IN<\/code> and a single predicate with both names:<\/p>\n\n\n\n<div class=\"wp-block-bstn-blocks-code-snippet bstn-blocks-code-snippet\" data-code-snippet=\"true\"><div class=\"bstn-blocks-code-snippet__title-bar\"><span class=\"bstn-blocks-code-snippet__title\">Code Example<\/span><button class=\"bstn-blocks-code-snippet__copy-trigger\" data-copy-to-clipboard=\"true\"><svg viewbox=\"0 0 12 13\" fill=\"none\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\" class=\"bstn-blocks-code-snippet__copy-trigger-icon\"><path d=\"M10.875.5h-7.5c-.633 0-1.125.516-1.125 1.125V2.75H1.125C.492 2.75 0 3.266 0 3.875v7.5A1.11 1.11 0 001.125 12.5h7.5c.61 0 1.125-.492 1.125-1.125V10.25h1.125c.61 0 1.125-.492 1.125-1.125v-7.5A1.14 1.14 0 0010.875.5zm-2.39 10.875h-7.22c-.093 0-.14-.047-.14-.14v-7.22c0-.07.047-.14.14-.14h.985v5.25a1.11 1.11 0 001.125 1.125h5.25v.984c0 .094-.07.141-.14.141zm2.25-2.25h-7.22c-.093 0-.14-.047-.14-.14v-7.22c0-.07.047-.14.14-.14h7.22c.07 0 .14.07.14.14v7.22c0 .093-.07.14-.14.14z\" fill=\"currentColor\"><\/path><\/svg><span data-copy-to-clipboard-text=\"true\">Copy<\/span><\/button><\/div><pre class=\"bstn-blocks-code-snippet__code-snippet-area match-braces line-numbers language-sql\" data-language=\"sql\"><code>SELECT * FROM employees WHERE first_name = \"Georgi\" OR first_name = \"Anneke\";<\/code><\/pre><\/div>\n\n\n\n<p class=\"is-style-bstn-paragraph-documentation-body\">In practice, <code>UNION<\/code> is most often used when combining different tables with the same schema or in more complex data engineering SQL code. For simpler queries coming from the same table, an equivalent result can usually be arrived upon without requiring its usage, as seen in above.<\/p>\n<\/div>\n\n\n\n<div class=\"wp-block-column is-layout-flow wp-block-column-is-layout-flow\" style=\"flex-basis:25%\"><\/div>\n<\/div>\n\n\n\n<div class=\"wp-block-bstn-blocks-content-navigation-footer bstn-blocks-content-nav-footer\"><div class=\"bstn-blocks-content-nav-footer__links-container\"><div class=\"bstn-blocks-content-nav-footer__link-container\"><p class=\"bstn-blocks-content-nav-footer__link-title\">Previous<\/p><a class=\"bstn-blocks-content-nav-footer__link\" href=\"https:\/\/brainstation.io\/learn\/sql\/having\"><span class=\"bstn-blocks-content-nav-footer__link-icon-wrapper bstn-blocks-content-nav-footer__link-icon-wrapper--left\"><svg xmlns=\"http:\/\/www.w3.org\/2000\/svg\" viewbox=\"0 0 18 18\" fill=\"none\" class=\"bstn-blocks-content-nav-footer__link-icon bstn-blocks-content-nav-footer__link-icon--left\"><path fill=\"currentColor\" d=\"M6.345 12.743a1 1 0 001.31 1.511l5.477-4.749a1 1 0 000-1.511l-5.477-4.75a1.001 1.001 0 00-1.31 1.512l4.606 3.993-4.606 3.994z\"><\/path><\/svg><\/span><span class=\"bstn-blocks-content-nav-footer__link-text\">SQL Having<\/span><\/a><\/div><div class=\"bstn-blocks-content-nav-footer__link-container\"><\/div><\/div><\/div>\n\n\n\n<div class=\"wp-block-bstn-blocks-container bstn-blocks-container bstn-blocks-container--dark-blue bstn-blocks-container--64 bstn-blocks-container--negative-container bstn-blocks-container--overflow-hidden\"><svg xmlns=\"http:\/\/www.w3.org\/2000\/svg\" viewbox=\"0 0 1140 621\" fill=\"none\" class=\"bstn-blocks-container__bg-flair\"><g opacity=\"0.55\"><path stroke=\"#3C4556\" strokelinecap=\"square\" d=\"M60.026 736.434V203.02\"><\/path><path stroke=\"#3C4556\" strokelinecap=\"square\" d=\"M60.364 436.132L-120 436.131l180.364.001zm0-99.873H-120 60.364zm0-99.872H-120 60.364zM128 536.004h-248 248z\" cliprule=\"evenodd\"><\/path><path fill=\"#3C4556\" fillrule=\"evenodd\" d=\"M57.518 535.982a2.286 2.286 0 114.572 0 2.286 2.286 0 01-4.572 0zm0-99.836a2.286 2.286 0 114.572-.002 2.286 2.286 0 01-4.572.002zm0-99.837a2.286 2.286 0 114.572-.002 2.286 2.286 0 01-4.572.002zm0-99.837a2.286 2.286 0 114.572-.002 2.286 2.286 0 01-4.572.002z\" cliprule=\"evenodd\"><\/path><\/g><g opacity=\"0.55\"><path stroke=\"#3C4556\" strokelinecap=\"square\" d=\"M979.195-28.206V397.98m81.185-524.745V397.98\"><\/path><path stroke=\"#3C4556\" strokelinecap=\"square\" d=\"M1141.45 168.46H964h177.45zm0 98.334H964h177.45zm0 98.333H964h177.45zm66.55-295H964h244z\" cliprule=\"evenodd\"><\/path><path fill=\"#3C4556\" fillrule=\"evenodd\" d=\"M1138.66 70.148a2.244 2.244 0 104.49 0 2.246 2.246 0 10-4.49-.001zm-80.21 0c0 1.243 1.01 2.251 2.25 2.251s2.25-1.008 2.25-2.251c0-1.243-1.01-2.251-2.25-2.251s-2.25 1.008-2.25 2.25zm-81.707 0a2.25 2.25 0 104.5.004 2.25 2.25 0 00-4.5-.005zm81.707 98.299a2.252 2.252 0 002.25 2.251 2.252 2.252 0 000-4.503 2.253 2.253 0 00-2.25 2.252zm-81.707 0a2.25 2.25 0 104.498 0 2.25 2.25 0 00-2.249-2.252 2.25 2.25 0 00-2.249 2.252zm161.917-.001a2.244 2.244 0 104.49 0 2.246 2.246 0 10-4.49 0zm0 98.299a2.244 2.244 0 104.49 0 2.246 2.246 0 10-4.49 0zm-80.21 0c0 1.243 1.01 2.251 2.25 2.251s2.25-1.008 2.25-2.251c0-1.243-1.01-2.251-2.25-2.251s-2.25 1.008-2.25 2.251zm-81.707 0a2.25 2.25 0 104.5.002 2.25 2.25 0 00-4.5-.002zm81.707 98.299c0 1.243 1.01 2.251 2.25 2.251s2.25-1.008 2.25-2.251c0-1.243-1.01-2.251-2.25-2.251s-2.25 1.008-2.25 2.251zm-81.707 0a2.25 2.25 0 104.5.002 2.25 2.25 0 00-4.5-.002zm161.917 0a2.244 2.244 0 104.49 0 2.246 2.246 0 10-4.49 0z\" cliprule=\"evenodd\"><\/path><\/g><\/svg><div class=\"bstn-blocks-container__wrapper bstn-blocks-container__wrapper--readable-width bstn-blocks-container__wrapper--negative-container\">\n<div class=\"wp-block-columns is-layout-flex wp-container-core-columns-is-layout-2 wp-block-columns-is-layout-flex\">\n<div class=\"wp-block-column is-layout-flow wp-block-column-is-layout-flow\">\n<div class=\"wp-block-bstn-blocks-heading bstn-blocks-heading bstn-blocks-heading--h2 has-text-align-left bstn-blocks-heading--divider\"><h2 class=\"bstn-blocks-heading__heading-element\">Learn SQL Today<\/h2><\/div>\n\n\n\n<p class=\"is-style-bstn-paragraph-documentation-body\">Get hands-on experience writing code with interactive tutorials in our free online learning platform.<\/p>\n\n\n\n<div style=\"height:16px\" aria-hidden=\"true\" class=\"wp-block-spacer\"><\/div>\n\n\n\n<ul class=\"wp-block-list is-style-kg-list-checklist-alternate\"><li>Free and fun<\/li><li>Designed for beginners<\/li><li>No downloads or setup required<\/li><\/ul>\n\n\n\n<div style=\"height:16px\" aria-hidden=\"true\" class=\"wp-block-spacer\"><\/div>\n\n\n\n<div class=\"wp-block-buttons is-layout-flex wp-block-buttons-is-layout-flex\">\n<div class=\"wp-block-button is-style-bstn-button-primary\"><a class=\"wp-block-button__link\" href=\"https:\/\/brainstation.io\/learn\/sql\" target=\"_blank\" rel=\"noreferrer noopener\">Get Started<\/a><\/div>\n<\/div>\n<\/div>\n\n\n\n<div class=\"wp-block-column is-layout-flow wp-block-column-is-layout-flow\">\n<figure class=\"wp-block-video\"><video autoplay loop muted src=\"https:\/\/d3ghupt9z9s6o0.cloudfront.net\/app\/uploads\/2022\/04\/13110644\/SQL-promo-clip.mp4\" playsinline><\/video><\/figure>\n<\/div>\n<\/div>\n<\/div><\/div>\n","protected":false},"excerpt":{"rendered":"<p>The SQL UNION clause can be used to concatenate the results of multiple SELECT statements together into a single result. In the general form, it is used as linkage between two or more SELECT statements as below: Since the results are being concatenated, it is a requirement that the schema (number of columns and data [&hellip;]<\/p>\n","protected":false},"featured_media":0,"parent":130267,"menu_order":0,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[],"tags":[],"class_list":["post-130458","codex-reference","type-codex-reference","status-publish","format-standard","hentry"],"acf":[],"_links":{"self":[{"href":"https:\/\/brainstation.io\/wp\/api\/wp\/v2\/codex-reference\/130458","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/brainstation.io\/wp\/api\/wp\/v2\/codex-reference"}],"about":[{"href":"https:\/\/brainstation.io\/wp\/api\/wp\/v2\/types\/codex-reference"}],"version-history":[{"count":7,"href":"https:\/\/brainstation.io\/wp\/api\/wp\/v2\/codex-reference\/130458\/revisions"}],"predecessor-version":[{"id":131363,"href":"https:\/\/brainstation.io\/wp\/api\/wp\/v2\/codex-reference\/130458\/revisions\/131363"}],"up":[{"embeddable":true,"href":"https:\/\/brainstation.io\/wp\/api\/wp\/v2\/codex-reference\/130267"}],"wp:attachment":[{"href":"https:\/\/brainstation.io\/wp\/api\/wp\/v2\/media?parent=130458"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/brainstation.io\/wp\/api\/wp\/v2\/categories?post=130458"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/brainstation.io\/wp\/api\/wp\/v2\/tags?post=130458"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}