MySQL - Drop INDEX or COLUMN with IF EXISTS check first

gistfile1.txt

# DROP INDEX
SELECT IF (
    EXISTS(
        SELECT * FROM INFORMATION_SCHEMA.statistics
        WHERE table_schema = DATABASE() AND TABLE_NAME = '<table_name>' AND index_name LIKE '<index_name>'
    )
    ,'ALTER TABLE `<table_name>` DROP INDEX `<index_name>`'
    ,'select "index <index_name> does not exist";') INTO @a;
PREPARE stmt1 FROM @a;
EXECUTE stmt1;
DEALLOCATE PREPARE stmt1;

# DROP COLUMN
SELECT IF (
    EXISTS(
        SELECT * FROM INFORMATION_SCHEMA.columns WHERE table_schema = DATABASE() AND TABLE_NAME = '<table_name>' AND COLUMN_NAME = '<column_name>' 
    )
    ,'ALTER TABLE `<table_name>` DROP COLUMN `<column_name>`'
    ,'select "column <index_name> does not exist";') INTO @a;
PREPARE stmt1 FROM @a;
EXECUTE stmt1;
DEALLOCATE PREPARE stmt1;