The EXPLAIN statement provides information about how MySQL executes statements: EXPLAIN works with SELECT , DELETE , INSERT , REPLACE , and UPDATE statements. … That is, MySQL explains how it would process the statement, including information about how tables are joined and in which order.

What is extra in explain MySQL?

The Extra column of EXPLAIN output contains additional information about how MySQL resolves the query. The following list explains the values that can appear in this column. Each item also indicates for JSON-formatted output which property displays the Extra value. For some of these, there is a specific property.

What is explain keyword in SQL?

The EXPLAIN keyword is used throughout various SQL databases and provides information about how your SQL database executes a query. … Instead of the usual result output, MySQL would then show its statement execution plan by explaining which processes take place in which order when executing the statement.