====== IF Statement ======

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

HPL/HQL supports multiple syntaxes for IF statement. 

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

Syntax:

<code language=sql>
IF boolean_expression THEN
  statements
[ELSIF | ELSEIF THEN
  statements
...]
[ELSE
  statements]
END IF;
</code>

**Example:**

<code language=sql>
IF state = 'CA' THEN
  code := 1;
ELSIF state = 'NY' THEN
  code := 2;
ELSIF state = 'MA' THEN
  code := 3;
ELSE
  code := 5;
END IF;
</code>

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

**Version**: HPL/SQL 0.1

===== IF - BEGIN - END - ELSE - BEGIN - END =====

Syntax:

<code language=sql>
IF boolean_expression 
  single_statement | block
[ELSE 
  single_statement | block];
</code>

**Example:**

<code language=sql>
IF state = 'CA'
  SET code = 1;
ELSE 
  SET code = 5;
</code>

<code language=sql>
IF state = 'CA'
BEGIN
  SET code = 1;
  SET type = 'A';
END
ELSE 
BEGIN
  SET code = 5;
  SET type = 'B';
END  
</code>

**Compatibility:** Microsoft SQL Server.

**Version**: HPL/SQL 0.1

===== .IF THEN =====

Syntax:

<code language=sql>
.IF boolean_expression THEN statement
</code>

**Example:**

<code language=sql>
.if errorcode <> 0 then .quit 1
</code>

**Compatibility:** Teradata BTEQ 

**Version**: HPL/SQL 0.3.31