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6 de dic. de 2016 · SELECT ifnull(nullif(field1,''),'empty or null') AS field1 FROM tablename; How it works: nullif is returning NULL if field is an empty string, otherwise returns the field itself. This has both the cases covered (the case when field is NULL and the case when it's an empty string).
The IFNULL () function returns a specified value if the expression is NULL. If the expression is NOT NULL, this function returns the expression.
Use COALESCE: SELECT COALESCE(field_a, field_b) COALESCE is an ANSI standard function that returns the first non-null value from the list of columns specified, processing the columns from left to right. So in the example, if field_a is null, field_b value will be displayed.
25 de abr. de 2021 · The MySQL IFNULL() function is used to return a specified value if the expression is NULL. If the expression is not NULL, IFNULL() returns the expression. Syntax of MySQL ISNULL()
If you want to check if a value is NULL or not, you can use IS NULL or IS NOT NULL in the WHERE clause. In this tutorial, we have introduced you to MySQL IFNULL function and shown you how to use the IFNULL function in the queries.
String-valued functions return NULL if the length of the result would be greater than the value of the max_allowed_packet system variable. See Section 7.1.1, “Configuring the Server”.. For functions that operate on string positions, the first position is numbered 1. For functions that take length arguments, noninteger arguments are rounded to the nearest integer.
2 de oct. de 2018 · In MySQL I am using IF operator to return "YES" if condition is valid and "NO" if it's not valid. SELECT IF(500<1000, "YES", "NO"); //RETURNS YES. I want to return nothing if the conditions is not valid. How can I do this?
