How Can I Concatenate Column Values from Multiple Rows in Oracle SQL?

Oracle SQL: Combining Column Values Across Multiple Rows

This guide demonstrates efficient methods for concatenating column values from multiple rows within Oracle SQL. The LISTAGG function provides a straightforward solution:

<code class="language-sql">SELECT pid, LISTAGG(Desc, ' ') WITHIN GROUP (ORDER BY seq) AS description
FROM B GROUP BY pid;</code>

This query performs the following actions:

1. Grouping by pid: Rows in table B are grouped based on the pid column.
2. Concatenating Desc values: The LISTAGG function concatenates values from the Desc column for each pid group. A space (' ') is used as the delimiter.
3. Ordering by seq: The concatenation order within each group is determined by the seq column.
4. Resulting description column: The concatenated string for each pid group is assigned to the description column.

To retrieve specific pid values, join this result set with table A.

Important Consideration: LISTAGG is optimized for VARCHAR2 columns. For other data types, explore alternative Oracle string aggregation techniques.

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