The difference between decimal and double in mysql

DECIMAL and DOUBLE are floating-point data types in MySQL, mainly different in precision and range. DECIMAL has a fixed precision and does not round, while DOUBLE precision depends on the hardware and may have rounding errors. DECIMAL allows a specified range, while DOUBLE has a fixed range and can handle larger numbers but with less precision. The storage space of DECIMAL depends on the precision, and the storage space of DOUBLE is fixed. Use DECIMAL for exact calculations and fixed precision, use DOUBLE for approximate calculations, large numbers, or space constraints.

The difference between DECIMAL and DOUBLE in MySQL

Answer:

DECIMAL and DOUBLE are two data types in MySQL, mainly used to store floating point numbers. The main difference between them is precision and range.

Detailed answer:

1. Accuracy

• DECIMAL: has fixed precision, starting from the decimal point Determined by the number of digits. It can store a number exactly to the specified number of digits without rounding errors.
• DOUBLE: is a floating point data type, the accuracy depends on the computer hardware and the algorithm used. It typically provides an accuracy of 15-16 significant figures, but rounding errors are possible.

2. Range

• DECIMAL: Allows the user to specify a range, including the total number of digits and the number of digits after the decimal point. This provides a high degree of control over range and precision.
• DOUBLE: Has a fixed range and depends on computer hardware and data type size. It can generally handle larger numbers than DECIMAL, but with less precision.

3. Storage space

• DECIMAL: Storage space depends on the specified precision. The more digits after the decimal point, the greater the storage space.
• DOUBLE: Always occupies a fixed amount of storage space, regardless of precision.

4. Performance

• DECIMAL: Better performance when precise calculations and fixed accuracy are required.
• DOUBLE: Better performance when approximate calculations are required or space is more important.

Selection suggestions:

• Use DECIMAL when high precision is required and rounding errors are not acceptable.
• Use DOUBLE when approximate calculations are required, when dealing with large numbers, or when space is limited.

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