{"id":8700,"date":"2024-03-14T08:33:12","date_gmt":"2024-03-14T08:33:12","guid":{"rendered":"https:\/\/www.silicloud.com\/blog\/how-to-delete-duplicate-data-in-sql\/"},"modified":"2025-08-03T08:32:30","modified_gmt":"2025-08-03T08:32:30","slug":"how-to-delete-duplicate-data-in-sql","status":"publish","type":"post","link":"https:\/\/www.silicloud.com\/blog\/how-to-delete-duplicate-data-in-sql\/","title":{"rendered":"Delete Duplicate Data in SQL: Step-by-Step"},"content":{"rendered":"<p>To remove duplicate data, you can use the DELETE statement and CTE (Common Table Expressions) in SQL. Here is an example:<\/p>\n<p>Firstly, using CTE to mark duplicate data rows as duplicates and retaining one of them.<\/p>\n<pre class=\"post-pre\"><code><span class=\"hljs-keyword\">WITH<\/span> CTE <span class=\"hljs-keyword\">AS<\/span> (\r\n  <span class=\"hljs-keyword\">SELECT<\/span> <span class=\"hljs-operator\">*<\/span>,\r\n         <span class=\"hljs-built_in\">ROW_NUMBER<\/span>() <span class=\"hljs-keyword\">OVER<\/span> (<span class=\"hljs-keyword\">PARTITION<\/span> <span class=\"hljs-keyword\">BY<\/span> column1, column2 <span class=\"hljs-keyword\">ORDER<\/span> <span class=\"hljs-keyword\">BY<\/span> (<span class=\"hljs-keyword\">SELECT<\/span> <span class=\"hljs-keyword\">NULL<\/span>)) <span class=\"hljs-keyword\">AS<\/span> rn\r\n  <span class=\"hljs-keyword\">FROM<\/span> your_table\r\n)\r\n<span class=\"hljs-keyword\">DELETE<\/span> <span class=\"hljs-keyword\">FROM<\/span> CTE\r\n<span class=\"hljs-keyword\">WHERE<\/span> rn <span class=\"hljs-operator\">&gt;<\/span> <span class=\"hljs-number\">1<\/span>;\r\n<\/code><\/pre>\n<p>In this example, assume your_table is a table containing duplicate data, with column1 and column2 being used to determine if the data is duplicate. The ROW_NUMBER() function assigns a row number to each data row within a group, with a row number greater than 1 indicating that the data row is a duplicate. Lastly, the DELETE statement is used to remove duplicate data rows.<\/p>\n<p>Please make sure to backup your data before carrying out the deletion operation to avoid accidentally deleting important data.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>To remove duplicate data, you can use the DELETE statement and CTE (Common Table Expressions) in SQL. Here is an example: Firstly, using CTE to mark duplicate data rows as duplicates and retaining one of them. WITH CTE AS ( SELECT *, ROW_NUMBER() OVER (PARTITION BY column1, column2 ORDER BY (SELECT NULL)) AS rn FROM [&hellip;]<\/p>\n","protected":false},"author":13,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_import_markdown_pro_load_document_selector":0,"_import_markdown_pro_submit_text_textarea":"","footnotes":""},"categories":[1],"tags":[11853,775,734,9486,5714],"class_list":["post-8700","post","type-post","status-publish","format-standard","hentry","category-uncategorized","tag-cte-sql","tag-data-cleaning","tag-delete-statement","tag-row_number","tag-sql-duplicates"],"yoast_head":"<!-- This site is optimized with the Yoast SEO Premium plugin v21.5 (Yoast SEO v21.5) - https:\/\/yoast.com\/wordpress\/plugins\/seo\/ -->\n<title>Delete Duplicate Data in SQL: Step-by-Step - Blog - Silicon Cloud<\/title>\n<meta name=\"description\" content=\"Learn how to remove duplicate rows in SQL using CTE and DELETE statements with our efficient syntax example.\" \/>\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.silicloud.com\/blog\/how-to-delete-duplicate-data-in-sql\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"Delete Duplicate Data in SQL: Step-by-Step\" \/>\n<meta property=\"og:description\" content=\"Learn how to remove duplicate rows in SQL using CTE and DELETE statements with our efficient syntax example.\" \/>\n<meta property=\"og:url\" content=\"https:\/\/www.silicloud.com\/blog\/how-to-delete-duplicate-data-in-sql\/\" \/>\n<meta property=\"og:site_name\" content=\"Blog - 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