New Table( "Testing Comparisons",
	Add Rows( 4 ),
	New Column( "A",
		Numeric,
		"Continuous",
		Format( "Best", 10 ),
		Set Values( [1, 2, 3, .] )
	),
	New Column( "B", Character, "Nominal", Formula( If( :A, "true", 1, "false" ) ) )
);
"true"
"true"
"true"
"false"
If(
	:A, "true",
If the value of A is nonmissing and nonzero, the result is "true". This comparison is true for the first three rows.
	1, "false"
);
Notes: 
a = "a";
If( a, "true", "false" );
When one value is false and another one is missing, Or() returns missing. Use OrMZ() to return false instead. See OrMZ(a, b) in the JSL Syntax Reference for details.
When one value is true and another one is missing, And() returns missing. Use AndMZ() to return false instead. See AndMZ(a, b) in the JSL Syntax Reference for details.
MatchMZ() is similar to Match() except that missing values are treated as 0.
IfMZ() is similar to If() except that missing values are treated as 0.
If you know that some values are missing, you can also compare with Is Missing(). The comparison in the preceding example can be rewritten to return "missing" for missing values:
If( :A, "true", Is Missing( :A ), "missing", "false" );
If the missing value could be 0, use the Zero Or Missing() function instead:
Zero Or Missing( A );

Help created on 10/11/2018