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29 lis 2019 · In MySQL you can use the COALESCE function: Returns the first non-NULL value in the list, or NULL if there are no non-NULL values. So you can simplify your query like this:
21 sie 2010 · I'm having a problem where when I try to select the rows that have a NULL for a certain column, it returns an empty set. However, when I look at the table in phpMyAdmin, it says null for most of the rows.
6 cze 2024 · We can use the function NULLIF to compare and check if the column contains null or empty values: SELECT id, name FROM Department WHERE NULLIF(TRIM(code), '') IS NULL; The NULLIF function evaluates its two arguments, returning NULL if they are equal.
A select_expression or where_definition in a SQL statement can consist of any expression using the functions described next. An expression that contains NULL always produces a NULL value unless otherwise indicated in the documentation for the operators and functions involved in the expression.
An expression that contains NULL always produces a NULL value unless otherwise indicated in the documentation for the operators and functions involved in the expression. All columns in the following example return NULL: mysql> SELECT NULL, 1+NULL, CONCAT('Invisible',NULL);
23 mar 2023 · If you’re working with a database, whether large or small, there might be occasions when you need to search for some entries containing strings. In this article, I’ll show you how to locate strings and substrings in MySQL and SQL Server.
In this article, we would like to show you how to find rows where the column value is an empty string in MySQL. Quick solution: SELECT * FROM `table_name` WHERE `column_name` = ''; If your column is NULL then the below query works: SELECT * FROM `table_name` WHERE `column_name` IS NULL; Practical example
