How to prepend a string to a column value in MySQL?

Question

I need a SQL update statement for updating a particular field of all the rows with a string "test" to be added in the front of the existing value.

For example, if the existing value is "try" it should become "testtry".

Answer 1

You can use the CONCAT function to do that:

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

If you want to get cleverer and only update columns which don't already have test prepended, try

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

Answer 2

UPDATE tablename SET fieldname = CONCAT("test", fieldname) [WHERE ...]