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How To Use Not Null For Multiple Columns In Sql, In this article, initially we will understand the SQL Server IsNull function, then we will move towards extending the IsNull functionality using Coalesce function. Insert distinct rows from the original table to the immediate table. Create a new table with the structure the same as the original table that you want to delete duplicate rows. The following code has 3 steps: create multiple copies for each row using cross join (also creating subject column in this case) create column "marks" and fill in relevant values using case expression ( ex: if subject is science then pick value from science column) remove any null By continuing to visit this site you agree to our use of browser storage technologies (localStorage, IndexedDB, OPFS), processing of technical data, and that you will not upload third-party personal data. ๐ SQL practice online: free practice tests with real-world queries, JOINs, subqueries, window functions, and interview-style problems for every skill level. May 27, 2026 ยท This article looks at how to use SQL IS NULL and SQL IS NOT NULL operations in SQL Server along with use cases and working with NULL values. The LEFT JOIN and LEFT OUTER JOIN keywords are equal - the OUTER keyword is optional. This guide will break down how to use IS NOT NULL for multiple columns in a WHERE clause, with practical examples, common pitfalls, and performance tips. B) Delete duplicate rows using an intermediate table The following shows the steps for removing duplicate rows using an intermediate table: 1. A NULL value represents an unknown, missing, or inapplicable data in a database field. erjgri, 4endd, x6bdjv, nyksc, thafic, fx, tylr, yrnf, xgx, zoo,