How to Concatenate MySQL Columns to Create Unique Identifiers?

Concatenating Columns in MySQL Tables for UniqueIdentifiers

MySQL provides a convenient method for combining values from multiple columns to create unique alphanumeric identifiers.

Question:

How can you concatenate data from two columns, SUBJECT and YEAR, in a MySQL table to generate a unique identifier?

Answer:

To concatenate column values, you can utilize the CONCAT function.

Example:

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

This query will concatenate the SUBJECT and YEAR columns with a space separator.

However, if you require an alphanumeric identifier with a more structured format, you can use the following query:

SET @rn := 0;

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

This query combines the SUBJECT and YEAR values with a hyphen separator and adds a zero-padded sequential number to ensure uniqueness. The LPAD function pads the number with leading zeros to maintain a consistent length for all identifiers.

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