The simple CASE statement (simple_case_statement) is a syntax element that can be used in a routine to define a database procedure (see CREATE DBPROC[EDURE] statement), a database function (see CREATE FUNCTION statement), or a trigger (see CREATE TRIGGER statement).
Syntax
<simple_case_statement> ::= CASE <expression> <simple_case_when_clause>... [<case_else_clause>] END [CASE] <simple_case_when_clause> ::= WHEN <literal>[,...] THEN <statement>; <case_else_clause> ::= ELSE <statement>;
A CASE statement (case_statement) allows the conditional execution of a statement depending on search conditions or equality of operands.
In the case of a simple CASE statement (simple_case_statement), the expression is compared with the literals. If the expression matches a literal, the associated statement is executed and the CASE statement ends.
CASE digit
WHEN 0 THEN toCHAR = 'zero';
WHEN 1 THEN toCHAR = 'one';
WHEN 2 THEN toCHAR = 'two';
WHEN 3 THEN toCHAR = 'three';
WHEN 4 THEN toCHAR = 'four';
WHEN 5 THEN toCHAR = 'five';
WHEN 6 THEN toCHAR = 'six';
WHEN 7 THEN toCHAR = 'seven';
WHEN 8 THEN toCHAR = 'eight';
WHEN 9 THEN toCHAR = 'nine';
ELSE STOP(-29000, 'no digit');
END CASE
If no matching literal or fulfilled search condition exists in a CASE statement, the statement defined in the ELSE branch is executed.
If there is no ELSE branch, the runtime error -28901 is returned.