Search results
31 mar 2009 · The best approach for me is to use REGEXP_REPLACE. Have a single string returned from the case statement, and in the outer query block select statement tokenize the string into different fields.
7 gru 2023 · If you want to do if-else-then logic in select, where or anywhere else in a statement, you need a case expression. This is a series of when clauses that the database runs in order: For example, if you want to map exam correct percentages to grade letters according to these rules:
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.
A WHEN clause can return the result of another CASE expression. This checks if the row is for a genuine result first. If it is, it returns the result of the grading CASE expression. It also has separate CASE expressions to see if a result is for a test exam or student, concatenating their output.
Evaluates each WHEN condition and if satisfied, assigns the value in the corresponding THEN expression. If none of the WHEN conditions are satisfied, it assigns the default value specified in the ELSE expression. If no ELSE expression is specified, the system automatically adds an ELSE NULL.
This Oracle tutorial explains how to use the Oracle / PLSQL CASE statement with syntax and examples. The Oracle / PLSQL CASE statement has the functionality of an IF-THEN-ELSE statement. Starting in Oracle 9i, you can use the CASE statement within a SQL statement.
