IF#
Примечание
Ниже приведена оригинальная документация Trino. Скоро мы ее переведем на русский язык и дополним полезными примерами.
Synopsis#
IF condition
THEN statements
[ ELSEIF condition THEN statements ]
[ ... ]
[ ELSE statements ]
END IF
Description#
The IF THEN
statement is an optional construct to allow conditional processing
in SQL routines. Each condition
following an IF
or ELSEIF
must evaluate to a boolean. The result of processing the expression
must result in a boolean true
value to process the statements
in the THEN
block. A result of false
results in skipping the THEN
block and moving to
evaluate the next ELSEIF
and ELSE
blocks in order.
The ELSEIF
and ELSE
segments are optional.
Examples#
FUNCTION simple_if(a bigint)
RETURNS varchar
BEGIN
IF a = 0 THEN
RETURN 'zero';
ELSEIF a = 1 THEN
RETURN 'one';
ELSE
RETURN 'more than one or negative';
END IF;
END
Further examples of varying complexity that cover usage of the IF
statement in
combination with other statements are available in the SQL routines examples
documentation.