Value :: operator-= - Subtract and assign result to first operator

The operation provides the result of subtracting two values. The operation is a self-operation returning the result in the first operand. The operation behaves differently for different data types of the left operand.

1. Numbers ( INT , REAL )

The operation builds the difference between the participating operands and returns the result with the data type of the first operand.

2. Text ( STRING , CHAR , CCHAR )

The second operand is converted into text which is searched and removed from the text in the first operand.

3. Boolean ( LOGICAL )

The second operand is converted into a Boolean value and the result is true , when exactly one of the operands is true (exclusive or).

4. Date

The second operator is converted into an integer number and subtracted as number of days to the date value in the first operand.

5. Time

The second operator is converted into an integer number and subtracted as number of hundredth seconds to the date value in the first operand.

6. DateTime

The second operator is converted into an integer number and subtracted as number of hundredth seconds to the timestamp value in the first operand.

7. Other

For all other data types for the left hand operand, the function throws an exception.