Converting CHAR Primary Key to INT in MySQL/MariaDB - mysql

Question

I have a table that uses CHAR as the primary key for customers. I am attempting to load this table into a schema such that the primary key should be an INT.
DROP TABLE IF EXISTS `customers`;
CREATE TABLE `customers` (
`customer_id` char(5) NOT NULL
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
INSERT INTO `customers` VALUES ('99944'),('99946'),('99976'),('A0014'),('A0049'),('A0124'),('C01AH'),('C01AQ'),('C01AW'),('C01AX'),('C01AY'),('C01AZ');
Fiddle
I have attempted variations on select cast(customer_id AS UNSIGNED) FROM customers; but only get back 0s for the non-int rows. How do I cast the non-int rows into a consistent INT result?
The ideal result would look like this:
For customer IDs that are solely integers, leave them alone.
For customer IDs that contain any letter, replace everything in the ID with a unique numerical identifier.
Expected result:
SELECT * FROM Customers;
`customer_id`
-------
99944
99946
99976
13871911
13871912
13871913
13872128
13872229
13872293
13872505
13872512
13872561

Answer 1

GMB did give me a other idea.
Using the HEX() and CONV(.., 16, 10) to convert from hexadecimals into decimales
Query
SELECT
customers.customer_id
, CASE
WHEN (customers.customer_id >> 0) > 0
THEN customers.customer_id >> 0
ELSE
CONV(HEX(customers.customer_id), 16, 10)
END
AS customer_id_int
FROM
customers;
Result
| customer_id | customer_id_int |
| ----------- | --------------- |
| 99944 | 99944 |
| 99946 | 99946 |
| 99976 | 99976 |
| A0014 | 279981338932 |
| A0049 | 279981339705 |
| A0124 | 279981404724 |
| C01AH | 288571343176 |
| C01AQ | 288571343185 |
| C01AW | 288571343191 |
| C01AX | 288571343192 |
| C01AY | 288571343193 |
| C01AZ | 288571343194 |
p.s
It might be generating a to large int you need to use a BIGINT datatype.
see demo
Updated
A other method to generate smaller int's (UNSIGNED INT) which uses a "SQL number generator", SUBSTRING(), ORD() and GROUP_CONCAT().
Query
SELECT
customers.customer_id
CASE
WHEN customers.customer_id >> 1 > 0
THEN customers.customer_id
ELSE
GROUP_CONCAT(
CASE
WHEN SUBSTRING(customers.customer_id, number_generator.number, 1) NOT BETWEEN 'A' AND 'Z'
THEN SUBSTRING(customers.customer_id, number_generator.number, 1) >> 1
ELSE ORD(SUBSTRING(customers.customer_id, number_generator.number, 1))
END
ORDER BY
number_generator.number ASC
SEPARATOR ''
)
END
) AS customer_id_int
FROM (
SELECT
record_1.number
FROM (
SELECT 1 AS number UNION SELECT 2 UNION SELECT 3 UNION SELECT 4 UNION SELECT 5
) AS record_1
) AS number_generator
CROSS JOIN
customers
GROUP BY
customers.customer_id
ORDER BY
customers.customer_id ASC
Result
| customer_id | customer_id_int |
| ----------- | --------------- |
| 99944 | 99944 |
| 99946 | 99946 |
| 99976 | 99976 |
| A0014 | 650002 |
| A0049 | 650024 |
| A0124 | 650012 |
| C01AH | 67006572 |
| C01AQ | 67006581 |
| C01AW | 67006587 |
| C01AX | 67006588 |
| C01AY | 67006589 |
| C01AZ | 67006590 |
see demo

Answer 2

With Maria DB >= 10.0.5, here is a solution to turn a string primary key to an integer primary key in a predictable manner :
SELECT
customer_id old_id,
CAST(
REGEXP_REPLACE(customer_id, '([^0-9])', ORD('$1'))
AS UNSIGNED
) new_id
FROM customers;
REGEXP_REPLACE() captures non-numeric characters (anywhere in the string) and ORD() turns each of them into its ordinal (numerical) represtation.
Demo on DB Fiddle :
old_id | new_id
:----- | -------:
99944 | 99944
9Z946 | 936946
A9CZ6 | 36936366
A0C14 | 3603614
0ABC0 | 3636360

Answer 3

Using MySQL 8.0 REGEXP_REPLACE:
select cast(REGEXP_REPLACE(customer_id,'[^0-9]','') AS UNSIGNED) FROM customers;
db<>fiddle demo