How to Convert Selected Values into a Comma-Separated String in MySQL?

Comma-Separated String of Selected Values in MySQL

In MySQL, converting selected values into a comma-separated string is possible using the GROUP_CONCAT() function. This function concatenates values in a specified column, separated by a character of choice, which in this case is a comma.

Consider the following code:

<code class="sql">SELECT id
FROM table_level
WHERE parent_id = 4;
</code>

This query retrieves the id column values from the table_level table where the parent_id column matches 4. The result is a list of values:

'5'
'6'
'9'
'10'
'12'
'14'
'15'
'17'
'18'
'779'

To obtain the desired comma-separated string, we can utilize the GROUP_CONCAT() function as follows:

<code class="sql">SELECT GROUP_CONCAT(id)
FROM table_level
WHERE parent_id = 4
GROUP BY parent_id;</code>

By grouping the results by parent_id and concatenating the id values with GROUP_CONCAT(), we obtain the comma-separated string:

"5,6,9,10,12,14,15,17,18,779"

This approach allows us to conveniently convert selected values into a comma-separated string, which is useful in various data manipulation scenarios.

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