Summary
Highlights
The second stage of query processing is query optimization. The query processor applies transformations to the internal data structure of the query, converting them into equivalent but more efficient representations. This involves selecting and applying appropriate rules for optimization.
An execution strategy is chosen in the process of query optimization to suit the processing of a query. This involves finding the most efficient way to execute the query to produce the desired results.
An example is provided: an SQL query asking for items where the price is greater than 100, and its corresponding relational algebra format is shown.
The video summarizes the query processing steps, emphasizing the input and output stages. It reiterates that the goal is to produce the query result efficiently.