Subtracts the value of the right variant from the left variant value

说锟斤拷

variant_sub ( mixed $left , mixed $right ) : mixed

Subtracts right from left.

锟斤拷锟斤拷

left: The left operand.
right: The right operand.

Note:
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锟斤拷锟斤拷值

**Variant Subtraction Rules**
If	Then
Both expressions are of the string type	Subtraction
One expression is a string type and the other a character	Subtraction
One expression is numeric and the other is a string	Subtraction.
Both expressions are numeric	Subtraction
Either expression is NULL	NULL is returned
Both expressions are empty	Empty string is returned

锟轿硷拷

variant_add() - "Adds" two variant values together and returns the result