All relational operators compare the values of the operands and return True (-1) or False (0) as the result. All relational operators are binary.
| Relational operator | Operator name | Operator function |
|---|---|---|
| < | Less than | A numeric comparison is made if both operands can be interpreted numerically. The operation returns the logical value of the evaluation of the comparison. |
| <= | Less than or equal | A numeric comparison is made if both operands can be interpreted numerically. The operation returns the logical value of the evaluation of the comparison. |
| > | Greater than | A numeric comparison is made if both operands can be interpreted numerically. The operation returns the logical value of the evaluation of the comparison. |
| >= | Greater than or equal | A numeric comparison is made if both operands can be interpreted numerically. The operation returns the logical value of the evaluation of the comparison. |
| = | Equals | A numeric comparison is made if both operands can be interpreted numerically. The operation returns the logical value of the evaluation of the comparison. |
| <> | Not equivalent to | A numeric comparison is made if both operands can be interpreted numerically. The operation returns the logical value of the evaluation of the comparison. |
| precedes |
Unlike the < operator no attempt is made to make a numeric interpretation of the argument values before the comparison. The operation returns true if the value to the left of the operator has a text representation which, in string comparison, comes before the text representation of the value on the right. Example: '1 ' precedes ' 2' returns FALSE whilst ' 1' precedes ' 2' returns TRUE as the ASCII value of a space (' ') is of less value than the ASCII value of a number. Compare this to: '1 ' < ' 2' returns TRUE and ' 1' < ' 2' returns TRUE |
|
| follows | Unlike the > operator no
attempt is made to make a numeric interpretation of the argument values
before the comparison. The operation returns true if the value to the
left of the operator has a text representation which, in string comparison,
comes after the text representation of the value on the right. Example: ' 2' follows '1 ' returns FALSE whilst ' 2' follows ' 1' returns TRUE as the ASCII value of a space (' ') is of less value than the ASCII value of a number. Compare this to: ' 2' > ' 1' returns TRUE and ' 2' > '1 ' returns TRUE |
