Order of precedence

The order of precedence defines in which order the elements of an expression are evaluated.

The following list describes the precedence order of expression elements.

For example, the MOD operator has a higher precedence as the * operator. When computing an expression like ( 33 MOD 2 * 5 ), the runtime system first evaluates (33 MOD 2) = 1 and then evaluates (1 * 5) = 5. The order of evaluation can be changed this by using parentheses: ( 33 MOD ( 2 * 5 ) ) = 3.

Table 1. Order of precedence list
P Syntax Element A Description Example
14 
CAST(var AS class)
 N Type casting 
CAST(var AS 
java.lang.Number)
14 
var INSTANCEOF class
 L Type checking 
var INSTANCEOF 
java.lang.Boolean
13 
UNITS
 L Single-qualifier interval 
(12) UNITS DAY
12 
+ (unary)
 R Unary plus 
+324
12 
- (unary)
 R Unary minus 
-324
11 
**
 L Exponentiation 
x ** 5
11 
MOD
 L Modulus 
x MOD 2
10 
*
 L Multiplication 
x * y
10 
/
 L Division 
x / y
9 
+
 L Addition 
x + y
9 
-
 L Subtraction 
x - y
8 
||
 L Concatenation 
"Amount:" || amount
7 
LIKE
 R String comparison 
mystring LIKE "A%"
7 
MATCHES
 R String comparison 
mystring MATCHES "A*"
6 
<
 L Less than 
var < 100
6 
<=
 L Less then or equal to 
var <= 100
6 
>
 L Greater than 
var > 100
6 
>=
 L Greater than or equal to 
var >= 100
6 
==
 L Equals 
var == 100
6 
<> or !=
 L Not equal to 
var <> 100
5 
IS NULL
 L Test for NULL 
var IS NULL
5 
IS NOT NULL
 L Test for NOT NULL 
var IS NOT NULL
4 
NOT
 L Logical inverse 
NOT ( a = b )
3 
AND
 L Logical intersection 
expr1 AND expr2
2 
OR
 L Logical union 
expr1 OR expr2
1 
ASCII(integer)
 R ASCII Character 
ASCII(32)
1 
CLIPPED
 R Delete trailing blanks 
DISPLAY string CLIPPED
1 
COLUMN integer
 R Begin line mode display 
PRINT COLUMN 32, "a"
1 
(integer) SPACES
 R Insert blank spaces 
DISPLAY "a" (5) SPACES
1 
SQLSTATE
 R SQL State Code 
IF SQLSTATE="IX000"
1 
SQLERRMESSAGE
 R SQL Error Message 
DISPLAY SQLERRMESSAGE
1 
USING
 R Format character string 
TODAY USING "yy/mm/dd"
1 
:=
 L Assignment 
var:= "abc"

In this table, the P column defines the precedence, from highest (14) to lowest (1). Note that some operators have the same precedence (i.e. are equivalent in evaluation order). The A column defines the direction of association (L=Left, R=Right, N=None).