如果列是文本和数字，我如何从列值大于某个值的mysql表中选择

Question

I have a table called "products" where one column is "SerialNumber". The problem is that this column is text latin1_swedish_ci and values are like "BC00001, BC0002, etc. i need to select all products where serial number is for example greater than some given serial number. i tried selecting like this:

SELECT * FROM 'products' WHERE 'SerialNumber' >= 'BC00563' 

But since this column is text, it' not working. I can't modify the table structure because the this table laready has 20.000 + records. Any help appreciated!

Answer 1

Assuming the value is always two characters followed by numbers, you can strip out the characters and convert the remaining values into number for the comparison, eg:

SELECT * 
FROM `products` 
WHERE `SerialNumber` >= 
    CASE WHEN 'BC00563' regexp '[A-Z]' THEN 
    CONVERT(SUBSTRING("BC00563", 3, LENGTH("BC00563")), UNSIGNED) 
    ELSE 'BC00563' END;

You can use the column name instead of constant value.