Question

I have many columns in a table with a name starting with field_t and I have to change that to field_c

For example, here is the ALTER TABLE statement for changing the name of one of the columns:

ALTER TABLE my_table CHANGE field_t_class field_c_class longtext;

How can I change all the columns that follow this pattern instead of doing it in a one by one basis?

Answer 1

You can generated the ALTERs like this

SELECT
    CONCAT(
           'ALTER TABLE ', C.TABLE_NAME, ' CHANGE ', 
           C.COLUMN_NAME, ' ', REPLACE(C.COLUMN_NAME, 'field_t', 'field_c')
           )
FROM
    INFORMATION_SCHEMA.COLUMNS C
WHERE
    C.COLUMN_NAME LIKE 'field[_]t[_]%';

You’ll also need to append DATA_TYPE etc and based on this CHARACTER_MAXIMUM_LENGTH,
NUMERIC_PRECISION, NUMERIC_SCALE, CHARACTER_SET_NAME and COLLATION_NAME…