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How is the case expression used in PostgreSQL?
The PostgreSQL CASE expression is the same as IF/ELSE statement in other programming languages. It allows you to add if-else logic to the query to form a powerful query. Since CASE is an expression, you can use it in any places where an expression can be used e.g., SELECT, WHERE, GROUP BY, and HAVING clause. The CASE expression has two forms:
Can a PostgreSQL case have multiple conditions?
PostgreSQL CASE s can have multiple conditions. There are a handful of entries in the table where the name of country and capital is the same. You can add this to your previously constructed CASE –
Which is the simple form in PostgreSQL?
PostgreSQL provides another form of the CASE expression called simple form as follows: CASE expression WHEN value_1 THEN result_1 WHEN value_2 THEN result_2 [WHEN …] ELSE else_result END
How to formulate conditional expressions in PostgreSQL?
Conditional expressions are one of the most fundamental elements of any programming paradigm. Common conditional expressions include if-else blocks and switch cases. You can formulate conditional expressions in PostgreSQL using WHEN-THEN case which is very similar to if-else blocks.
When to use if else in PostgreSQL?
One of the most crucial and powerful out of all of them is the if-else statement. This statement allows us to execute certain code only when some condition is fulfilled. If not, then some other code might be executed.
Can you have multiple case’s in PostgreSQL?
PostgreSQL CASE s can have multiple conditions. There are a handful of entries in the table where the name of country and capital is the same. You can add this to your previously constructed CASE – Another exciting thing about CASE s is that you can pair them with aggregate functions like SUM ().
Which is an example of a case statement in pgSQL?
If the result of the search-expression does not match expression in the when sections and the else section does not exist, the case statement will raise a case_not_found exception. The following is an example of the simple case statement. This example first selects the film with id 100.