How can I cast a `VARCHAR` to an `INT` in MySQL?

To cast a VARCHAR to an INT in MySQL, you can use the following approaches:

1. Using the CAST Function

The CAST function explicitly converts a VARCHAR value to an INT.

• AS UNSIGNED: Converts the string to a non-negative integer.
• AS SIGNED: Converts the string to an integer that can be negative or positive.

2. Using the CONVERT Function

The CONVERT function also converts a VARCHAR to an INT.

3. Using Implicit Conversion

MySQL can implicitly convert a VARCHAR to an INT when performing numeric operations.

• Adding 0 forces MySQL to interpret the VARCHAR value as a number.

Considerations

1. Non-Numeric Characters:
   • If the VARCHAR contains non-numeric characters, MySQL extracts the leading numeric part and discards the rest.
   • Example: '123abc' will convert to 123.
2. Invalid Values:
   • If the VARCHAR does not contain a valid number, it converts to 0.
3. Performance:
   • Explicit conversion using CAST or CONVERT is generally more reliable and recommended for clarity and maintainability.

Choose the method based on your requirements and the format of the data in the VARCHAR column.