Choosing the right data type is the first step in good database design. MySQL provides numeric, string, date/time, and JSON types, and the right choice affects storage size, accuracy, and query speed — all critical when your tables feed analytics reports.
Key Points
- Numeric: INT, BIGINT, DECIMAL (exact, ideal for money), FLOAT/DOUBLE (approximate)
- String: CHAR (fixed length), VARCHAR (variable), TEXT (long content), ENUM
- Date/time: DATE, DATETIME, TIMESTAMP, TIME, YEAR
- JSON type for semi-structured data since MySQL 5.7
- Use DECIMAL for financial values to avoid floating-point rounding errors
- Smaller types = smaller indexes = faster analytical queries
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