What is the difference between double and decimal in MySQL?

In MySQL, both double and decimal are numerical data types, but they have some important differences between them.

1. Storage method: double uses floating-point numbers for storage, while decimal uses fixed-point numbers for storage.
2. Precision and Range: The double is a floating-point number that can store a large range of data and represent a high precision with many decimal places, but its accuracy is relatively lower. In contrast, decimal is a fixed-point number with a fixed precision and range, allowing for exact storage of decimals. Decimal supports user-defined precision and range.
3. Storage space: Double typically requires less storage space because it uses floating-point numbers, while decimal requires more storage space because it stores precise decimals using fixed-point numbers.
4. Accurate calculations: Due to the fact that double is a floating point number, it may experience precision loss issues during calculations. On the other hand, decimal being a fixed point number, can perform precise calculations without any precision loss problems.

Therefore, if precise calculations, storing exact decimals, or ensuring the accuracy of calculation results is necessary, the decimal type should be used. If high precision is not required and a large range of data needs to be stored, the double type can be used.