For operands:
- If the operand is character, the format is the default format for FLOAT.
- If the operand is numeric, date, or interval, the format is the same format as x.
- If the operand is UDT, the format is the format for the data type to which the UDT is implicitly cast.
The value_expression cannot be a reference to a view column derived from a function, and cannot contain any ordered analytical or aggregate functions.
VARIANCE OF A SAMPLE is valid only for numeric data.
Nulls are not included in the result computation.
Division by zero results in NULL rather than an error.