How to Generate Unique Alphanumeric Numbers by Concatenating MySQL Columns?

Concatenating MySQL Columns for Unique Number Generation

When working with MySQL tables, it may be necessary to generate unique numbers that combine data from multiple columns. In a scenario where a table contains two columns named SUBJECT and YEAR, the objective is to create an alphanumeric unique number that incorporates the values of both fields.

One approach to achieve this is through the CONCAT function, as demonstrated in the following code:

SELECT CONCAT(`SUBJECT`, ' ', `YEAR`) FROM `table`

This query would concatenate the values of the SUBJECT and YEAR columns, separated by a space. However, to create a unique number, a more intricate method is required.

An alternative solution involves using a combination of LPAD and a variable to generate a unique suffix. The updated query is as follows:

SET @rn := 0;

SELECT CONCAT(`SUBJECT`,'-',`YEAR`,'-',LPAD(@rn := @rn+1,3,'0'))
FROM `table`

This query first initializes a variable named @rn to 0. It then concatenates the values of SUBJECT and YEAR, adding a hyphen as a separator. Finally, it utilizes the LPAD function to left-pad the incremented value of @rn with zeros to achieve a consistent length of three characters.

By implementing this approach, a unique alphanumeric number can be generated for each row in the MySQL table, combining the data from both the SUBJECT and YEAR columns.

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