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I have a select statement where I want to make the select conditional like this:
IFNULL(field_a, field_a, field_b) so that it checks field a. If a is null then the select would be field b.
Is that possible ?
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MySQL IFNULL() Function The IFNULL() function returns a specified value if the expression is NULL. If the expression is NOT NULL, this function returns the expression.
MySQL IFNULL() takes two expressions and if the first expression is not NULL, it returns the first expression. Otherwise, it returns the second expression. Depending on the context in which it is used, it returns either numeric or string value. An expression.
The syntax for the IF-THEN-ELSE statement in MySQL is: IF condition1 THEN {... statements to execute when condition1 is TRUE...} [ ELSEIF condition2 THEN {...
The IS NOT NULL condition is used in SQL to test for a non-NULL value. It returns TRUE if a non-NULL value is found, otherwise it returns FALSE. It can be used in a SELECT, INSERT, UPDATE, or DELETE statement.
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. However, this function will return NULL if there is no non-null value from the columns specified.
It's supported on MySQL (I've used it on 4.1), SQL Server (since v2000), Oracle 9i+...
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and another way to skin that cat (flexible for not just null comparisons)...
select if(field_a is not null, field_a, field_b) from... If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
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