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Use the LEN function to check for null or empty values. You can just use LEN(@SomeVarcharParm) > 0. This will return false if the value is NULL, '', or ' '. This is because LEN(NULL) returns NULL and NULL > 0 returns false. Also, LEN(' ') returns 0. See for yourself run:
In most situations text or character varying should be used instead. Do not confuse char (n) with other, useful, character types varchar (n), varchar, text or "char" (with double-quotes). In char (n) an empty string is not different from any other string consisting of only spaces.
6 cze 2024 · The ISNULL function in MS SQL takes two arguments: the first is a value or column name, and the second is the default value if the first argument is null. This query retrieves rows where the code column is either null, an empty string, or contains only spaces.
The SQL Server ISNULL() function lets you return an alternative value when an expression is NULL: SELECT ProductName, UnitPrice * (UnitsInStock + ISNULL(UnitsOnOrder, 0)) FROM Products;
Using the ISNULL() function we could write the following query which will update any row in the Product table that has a NULL value in the Color column to an empty string. UPDATE [Production].[Product] SET Color = ISNULL(Color,'');
3 wrz 2024 · Replaces NULL with the specified replacement value. Transact-SQL syntax conventions. Syntax ISNULL ( check_expression , replacement_value ) Arguments check_expression. The expression to be checked for NULL. check_expression can be of any type. replacement_value. The expression to be returned if check_expression is NULL.
5 lis 2012 · In this video, I show you how to filter for SQL Null or Empty String in SQL Server 2012. I will also show you a trick to make it easier to filter for both.
