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2 Ιουλ 2010 · Based on my condition, (for eg. length), I want to execute different SQL statement. Problematic sample query is as follows: select case. when char_length('19480821') = 8. then select count(1) from Patient. when char_length('19480821')=10. then select count(1) from Doctor. end.
The CASE expression provides conditional SQL expressions. You can use case expressions anywhere you can use an expression. The syntax of the CASE expression is as follows: CASE expression. WHEN expression THEN expression [, …] [ ELSE expression ] END. You cannot use a subquery as a value expression in a CASE statement.
7 Μαΐ 2017 · The simple way to achieve this goal is to add a CASE expression to your SELECT statement. In this article, we'll introduce you to the syntax, formats, and uses of the CASE expression. The CASE expression is a conditional expression: it evaluates data and returns a result.
Oracle CASE expression allows you to add if-else logic to SQL statements without having to call a procedure. The CASE expression evaluates a list of conditions and returns one of the multiple possible results. You can use a CASE expression in any statement or clause that accepts a valid expression.
In a simple CASE expression, Oracle Database searches for the first WHEN... THEN pair for which expr is equal to comparison_expr and returns return_expr. If none of the WHEN... THEN pairs meet this condition, and an ELSE clause exists, then Oracle returns else_expr. Otherwise, Oracle returns null.
The CASE expression goes through conditions and returns a value when the first condition is met (like an if-then-else statement). So, once a condition is true, it will stop reading and return the result. If no conditions are true, it returns the value in the ELSE clause.
2 Ιουν 2023 · The syntax of the SQL CASE expression is: CASE [expression] WHEN condition_1 THEN result_1. WHEN condition_2 THEN result_2 ... WHEN condition_n THEN result_n. ELSE result. END case_name. The CASE statement can be written in a few ways, so let’s take a look at these parameters. Parameters of the CASE Statement.
