What is the difference between decimal and number in MySQL?

In MySQL, decimal and number are both data types used for storing precise numerical values. However, they have some differences in certain aspects.

1. Storage space: Decimal uses variable length storage space, while number uses fixed length storage space. This means that decimal can adjust storage space dynamically based on data size, while number requires a fixed storage space.
2. Precision and range: The precision and range of decimals can be adjusted as needed, allowing for the storage of numbers with any precision and range. On the other hand, the precision and range of number types are fixed, depending on the specific number type chosen (for example, number(10,2) represents a maximum of 10 digits, with 2 decimal places).
3. Calculation method: When using the decimal data type for calculations, all decimal places are retained without rounding. In contrast, when using the number data type for calculations, rounding is done based on the defined precision.
4. Usage scenarios: Decimal is typically used in scenarios requiring high-precision calculations, such as financial systems and currency calculations. Number, on the other hand, is generally used for general numerical calculations like statistical analysis and scientific computation.

In general, the decimal type is more flexible and precise, while the number type is simpler and easier to use. The specific choice between the two types depends on the data requirements and usage scenarios.