Using IF … THEN … ELSE Statements

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The IF THEN ELSE statement selects alternative courses of action by testing a specified condition. The syntax of IF THEN ELSE is as follows:

IF (<condition>)

 THEN <compound_statement>
[ELSE <compound_statement>]
<compound_statement> = {<block> |
statement;}

The condition clause is an expression that must evaluate to TRUE to execute the statement or block following THEN. The optional ELSE clause specifies an alternative statement or block to be executed if condition is FALSE.

The following lines of code illustrate the use of IF THEN, assuming the variables LINE2, FIRST, and LAST have been previously declared:

. . .
IF (FIRST IS NOT NULL)
 THEN LINE2 = FIRST || ' ' || LAST;
ELSE LINE2 = LAST;
. . .

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