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12 gru 2013 · Yes, you could also use COALESCE(@value,'')='' which is based on the ANSI SQL standard: SELECT CASE WHEN COALESCE(@value,'')='' THEN 'Yes, it is null or empty' ELSE 'No, not null or empty' END AS IsNullOrEmpty DEMO
To check if variable is null or empty use this: IF LEN(ISNULL(@var, '')) = 0 -- Is empty or NULL ELSE -- Is not empty and is not NULL
6 cze 2024 · In this article, we explored several techniques for identifying NULLs and empty values within a column. In SQL, NULL represents missing or unknown data, covering cases where data is absent or uncertain. We can use empty strings for similar purposes, allowing us to differentiate between the absence and nonexistence of data.
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;
4 sty 2011 · NULL means absence of value (i.e. there is no value), while empty string means there is a string value of zero length. For example, say you have a table to store a person' data and it contains a Gender column.
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.
When inserting such data (without email) into the table, there are two available choices: set cell to NULL or set it to empty string (''). Let's assume that I'm aware of all the technical implications of choosing one solution over another and I can create correct SQL queries for either scenario.
