Consider SQL queries Q1, Q8, Q1B, Q4, Q27 in Chapter 5.
(a) Draw at least two query trees that can represented each of these queries. Under what circumstances would you use each of your query trees?
(b) Draw the initial query tree for each of these queries; then show how the query tree is optimized by the algorithm outlined in section 19.7.
(c) For each query, compare your on query trees of part (a) and the initial and final query trees of part (b).