Comparison operators
Used to compare expressions and return a Boolean result.
Syntax:
result = expression1 comparisonoperator expression2
result = object1 Is object2
result = string Like pattern
- result
- Any numeric variable.
- expression
- Any expression.
- comparisonoperator
- Any of
<,<=,>,>=,=,<>. - object
- Any object reference.
- string
- Any string expression.
- pattern
- Any string expression or range of characters.
The following table lists the comparison operators and the conditions that determine whether result is True, False, or Null:
| Operator | True if | False if | Null if |
|---|---|---|---|
< (Less than) | expression1 < expression2 | expression1 >= expression2 | expression1 or expression2 = Null |
<= (Less than or equal to) | expression1 <= expression2 | expression1 > expression2 | expression1 or expression2 = Null |
> (Greater than) | expression1 > expression2 | expression1 <= expression2 | expression1 or expression2 = Null |
>= (Greater than or equal to) | expression1 >= expression2 | expression1 < expression2 | expression1 or expression2 = Null |
= (Equal to) | expression1 = expression2 | expression1 <> expression2 | expression1 or expression2 = Null |
<> (Not equal to) | expression1 <> expression2 | expression1 = expression2 | expression1 or expression2 = Null |
INFO
The Is and Like operators have their own dedicated comparison semantics and are documented separately.
The = symbol is also the assignment operator (*variable* = *expression*). The context --- whether = appears in an expression or at the top of a statement --- determines which meaning applies; no explicit choice between them is required.
When comparing two expressions, determining whether they are being compared as numbers or as strings can be non-obvious. The following table shows how the expressions are compared, or the result when either expression is not a Variant:
| If | Then |
|---|---|
| Both expressions are numeric (Byte, Boolean, Integer, Long, LongLong, Single, Double, Date, Currency) | Perform a numeric comparison. |
| Both expressions are String | Perform a string comparison. |
| One expression is numeric and the other is a Variant that is, or can be, a number | Perform a numeric comparison. |
| One expression is numeric and the other is a string Variant that can't be converted to a number | A Type Mismatch error occurs. |
| One expression is a String and the other is any Variant except a Null | Perform a string comparison. |
| One expression is Empty and the other is a numeric data type | Perform a numeric comparison, using 0 as the Empty expression. |
| One expression is Empty and the other is a String | Perform a string comparison, using "" as the Empty expression. |
If expression1 and expression2 are both Variant expressions, their underlying type determines how they are compared:
| If | Then |
|---|---|
| Both Variant expressions are numeric | Perform a numeric comparison. |
| Both Variant expressions are strings | Perform a string comparison. |
| One Variant expression is numeric and the other is a string | The numeric expression is less than the string expression. |
| One Variant expression is Empty and the other is numeric | Perform a numeric comparison, using 0 as the Empty expression. |
| One Variant expression is Empty and the other is a string | Perform a string comparison, using "" as the Empty expression. |
| Both Variant expressions are Empty | The expressions are equal. |
When a Single is compared to a Double, the Double is rounded to the precision of the Single. If a Currency is compared with a Single or Double, the Single or Double is converted to a Currency. For Currency, any fractional value less than .0001 may be lost, which can cause two values to compare as equal when they are not.
String comparisons are governed by the module's Option Compare setting --- Binary (the default; case-sensitive, ordinal) or Text (case-insensitive, locale-sensitive).
Example
Dim MyResult, Var1, Var2
MyResult = (45 < 35) ' Returns False.
MyResult = (45 = 45) ' Returns True.
MyResult = (4 <> 3) ' Returns True.
MyResult = ("5" > "4") ' Returns True.
Var1 = "5": Var2 = 4 ' Initialize variables.
MyResult = (Var1 > Var2) ' Returns True (string compared as string).
Var1 = 5: Var2 = Empty
MyResult = (Var1 > Var2) ' Returns True (Empty treated as 0).
Var1 = 0: Var2 = Empty
MyResult = (Var1 = Var2) ' Returns True.