How many digits is the DECIMAL used for expressions containing only exact values with fractional part?

Solution (By Examveda Team)

This question is about the DECIMAL data type in MySQL, which is used to store numbers with decimal points.

The question asks about how many digits are used to represent the fractional part (the part after the decimal point) of a number stored as DECIMAL when it contains only exact values.

To answer this, we need to understand how DECIMAL stores numbers. In MySQL, DECIMAL uses a fixed-point representation, which means the number of digits before and after the decimal point are set when you define the column. The number of digits for the fractional part is determined by the precision and scale you specify for the DECIMAL column.

The maximum precision for DECIMAL in MySQL is 65, meaning it can store a total of 65 digits (before and after the decimal point). The scale defines the number of digits after the decimal point.

Since the question asks about the fractional part, we need to focus on the scale.

The maximum scale for DECIMAL in MySQL is 30. This means that the maximum number of digits that can be used to represent the fractional part of a DECIMAL number is 30.

However, the question specifically asks about the number of digits for expressions containing only exact values. This means that the values are precise and not rounded.

In such cases, the number of digits used for the fractional part is determined by the scale of the DECIMAL column.

Therefore, the answer is 30, which represents the maximum number of digits for the fractional part in a DECIMAL column.

None of the given options (A, B, C, or D) are correct.