How do I add a string to the beginning of values in a MySQL column?

Prepending a String to Column Values in MySQL

Updating a column's value to include a prepended string in MySQL requires a tailored SQL update statement. Suppose you need to add "test" to the beginning of an existing value in a specific field across multiple rows.

To achieve this, the CONCAT function comes to your aid. It allows you to concatenate multiple strings together.

UPDATE tbl SET col=CONCAT('test',col);

This query updates the "col" field in the "tbl" table by prefixing the existing value with "test." For instance, if the current value of "col" is "try," it will become "testtry."

However, if you want to ensure that "test" is not prepended to values that already contain it, you can utilize a more refined approach:

UPDATE tbl SET col=CONCAT('test',col)
WHERE col NOT LIKE 'test%';

This enhanced query employs the LIKE operator to check if the existing value does not start with "test." This allows for selective updates, maintaining the integrity of existing values that already meet the desired criteria.

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