Is There a LISTAGG Equivalent in Older Oracle Versions to MySQL's GROUP_CONCAT?

Is there an equivalent of GROUP_CONCAT for MySQL in Oracle?

Question:

How to concatenate multiple values ​​in a specified column into a single comma separated string in Oracle? The input data follows a specific format and the desired output should group and concatenate values ​​for each unique key.

Answer:

For Oracle 11g and above:

Use the LISTAGG function:

<code class="language-sql">SELECT 
    col1,
    LISTAGG(col2, ', ') WITHIN GROUP (ORDER BY col2) "names"
FROM table_x
GROUP BY col1</code>

For Oracle 10g and lower:

One way is to create a custom function:

<code class="language-sql">CREATE OR REPLACE FUNCTION get_comma_separated_value (input_val  IN  NUMBER)
  RETURN VARCHAR2
IS
  return_text  VARCHAR2(10000) := NULL;
BEGIN
  FOR x IN (SELECT col2 FROM table_name WHERE col1 = input_val) LOOP
    return_text := return_text || ',' || x.col2 ;
  END LOOP;
  RETURN LTRIM(return_text, ',');
END;
/</code>

How to use:

<code class="language-sql">SELECT col1, get_comma_separated_value(col1) FROM table_name</code>

Note: Oracle versions prior to 11g have limited support for the WM_CONCAT function, but its use is deprecated due to potential issues (see Oracle documentation for details).

In MySQL (for reference only):

GROUP_CONCAT function available:

<code class="language-sql">SELECT col1, GROUP_CONCAT(col2) FROM table_name GROUP BY col1</code>

The above is the detailed content of Is There a LISTAGG Equivalent in Older Oracle Versions to MySQL's GROUP_CONCAT?. For more information, please follow other related articles on the PHP Chinese website!