Apache Hive : HPL/SQL - IF Statement

IF statement executes a set of statements depending on the value of a boolean expression.

HPL/SQL supports multiple syntaxes for IF statement.

IF - THEN - ELSIF/ELSEIF - ELSE - END IF

Syntax:

IF boolean_expression THEN
  statements
[ELSIF | ELSEIF THEN
  statements
...]
[ELSE
  statements]
END IF;

Example:

IF state = 'CA' THEN
  code := 1;
ELSIF state = 'NY' THEN
  code := 2;
ELSIF state = 'MA' THEN
  code := 3;
ELSE
  code := 5;
END IF;

Compatibility: Oracle, Teradata, IBM DB2, MySQL, PostgreSQL, Netezza.

IF - BEGIN - END - ELSE - BEGIN - END

Syntax:

IF boolean_expression 
  single_statement | block
[ELSE 
  single_statement | block];

Example:

IF state = 'CA'
  SET code = 1;
ELSE 
  SET code = 5;

IF state = 'CA'
BEGIN
  SET code = 1;
  SET type = 'A';
END
ELSE 
BEGIN
  SET code = 5;
  SET type = 'B';
END  

Compatibility: Microsoft SQL Server.