Which column in an explain statement indicates the estimate of rows examined by the query?

In the context of an explain statement, the "Rows" column provides the estimate of the number of rows examined by the query. This information is valuable for understanding how efficiently a query will execute and can help identify potential performance issues. When you analyze the output of an explain statement, observing how many rows are estimated to be examined versus how many are actually returned can give insights into the effectiveness of the query's execution plan. This estimation allows developers and database administrators to optimize their queries by providing a clearer picture of the amount of data being processed.

The other columns, while important, serve different purposes. The "Ref" column typically indicates references to underlying tables or indexes, the "Filtered" column shows the number of rows filtered out by criteria, and the "Returned" column reflects the number of rows that are actually returned after execution. Each of these columns contributes to understanding query performance, but the "Rows" column is specifically dedicated to the estimate of rows examined.