Special Function (special_function)
There are certain special
functions (special_function) that are not restricted to specific data types.Syntax
<special_function> ::=
VALUE (<expression>,<expression>,...)
| GREATEST (<expression>,<expression>,...)
| LEAST (<expression>,<expression>,...)
| DECODE (<check_expression>,<search_and_result_spec>,...[,<default_expression>])
| <case_function>
<check_expression> ::= <expression>
<search_and_result_spec> ::= <search_expression>,<result_expression>
<default_expression> ::= <expression>
<result_expression> ::= <expression>
<case_function> ::= <simple_case_function>|<searched_case_function>