# Column Default Values

+ The default value for numeric and most string type columns must be a constant
+ Default values for time and date type columns can use function as default values
+ Default values cannot be set for BLOB, TEXT, and JSON
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Default values for TiDB table columns
- The default value for numeric and most string type columns must be a constant, not a function or an expression
- Default values for time and date type columns can be used as default values using function such as NOW, CURRENT_TIMESTAMP, LOCALTIME, LOCALTIMESTAMP
- Default values cannot be set for BLOB, TEXT, and JSON