How Can I Sum Comma-Separated Values in MySQL 4 Without Using Stored Procedures?

Summing a Comma Separated Column in MySQL 4 (Not 5)

In MySQL 4, performing an operation on a comma-separated column without using external tools can be challenging due to the lack of advanced string manipulation capabilities. This article explores alternative approaches for summing such columns in MySQL 4.

Non-Trivial String Manipulations

Unfortunately, MySQL 4 does not provide support for stored procedures, which offer more sophisticated string manipulation functions. This makes it difficult to perform complex calculations on comma-separated values directly using SQL statements.

Alternative Approaches

One possible approach is to upgrade to MySQL 5 or later, which includes support for stored procedures and allows for the creation of custom functions to handle such operations. Here is one such function that can be used in MySQL 5.0 to sum comma-separated values:

<code class="sql">DELIMITER //
CREATE FUNCTION SUM_OF_LIST(s TEXT)
  RETURNS DOUBLE
  DETERMINISTIC
  NO SQL
BEGIN
  DECLARE res DOUBLE DEFAULT 0;
  WHILE INSTR(s, ",") > 0 DO
    SET res = res + SUBSTRING_INDEX(s, ",", 1);
    SET s = MID(s, INSTR(s, ",") + 1);
  END WHILE;
  RETURN res + s;
END //
DELIMITER ;</code>

This function can be used as follows:

<code class="sql">mysql> SELECT SUM_OF_LIST("5,2.1") AS Result;
+--------+
| Result |
+--------+
|    7.1 |
+--------+</code>

Limitations

While this function provides a solution for summing comma-separated values in MySQL 5.0 , it is important to note that it may not handle all scenarios gracefully. For example, it treats trailing commas and empty values differently compared to other environments. Therefore, careful validation and testing are recommended when using this approach.

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