Used to compare expressions.

result=expression1 comparisonoperator expression2result=object1Isobject2

*result*- Any numeric variable.
*expression*- Any expression.
*comparisonoperator*- Any comparison operator.
*object*- Any object name.

The **Is** operator has specific comparison functionality that differs from the operators in the following table. The following table contains a list of the comparison operators and the conditions that determine whether *result* is **True**, **False**, or Null:

Operator | Description | 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 |

When comparing two expressions, you may not be able to easily determine whether the expressions are being compared as numbers or as strings.

The following table shows how expressions are compared or what results from the comparison, depending on the underlying subtype:

If | Then |
---|---|

Both expressions are numeric | Perform a numeric comparison. |

Both expressions are strings | Perform a string comparison. |

One expression is numeric and the other is a string | The numeric expression is less than the string expression. |

One expression is Empty and the other is numeric |
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 a zero-length string ("") as the Empty expression. |

Both expressions are Empty |
The expressions are equal. |

= Operator | Is Operator | Operator Precedence | Operator Summary