SET @dbname = DATABASE();
SET @tablename = "poisons";
SET @targetname = "positions";

SET @exists = (
    SELECT COUNT(*) FROM INFORMATION_SCHEMA.TABLES 
    WHERE table_schema = @dbname 
    AND table_name = @tablename
);

SET @target_exists = (
    SELECT COUNT(*) FROM INFORMATION_SCHEMA.TABLES 
    WHERE table_schema = @dbname 
    AND table_name = @targetname
);

SET @stmt = IF(@exists > 0 AND @target_exists = 0, 
    CONCAT('RENAME TABLE ', @tablename, ' TO ', @targetname), 
    'SELECT 1'
);

PREPARE stmt FROM @stmt;
EXECUTE stmt;
DEALLOCATE PREPARE stmt;