c) Write a query to display the patron ID and the average number of days that patron keeps books during a checkout. Limit the results to only patrons who have at least three checkouts. Sort the results in descending order by the average days the book is kept. Sample Output:-Average days kept by Patron PAT_ID Average Days Kept 7 6.67 5.67 5.5 5.33 4.5 1160 1185 1165 1207 1209 1172 1183 1181 1171 1161 1210 1229 4.33 3.67 3.67 3.33 2.33 2
SQL
SQL stands for Structured Query Language, is a form of communication that uses queries structured in a specific format to store, manage & retrieve data from a relational database.
Queries
A query is a type of computer programming language that is used to retrieve data from a database. Databases are useful in a variety of ways. They enable the retrieval of records or parts of records, as well as the performance of various calculations prior to displaying the results. A search query is one type of query that many people perform several times per day. A search query is executed every time you use a search engine to find something. When you press the Enter key, the keywords are sent to the search engine, where they are processed by an algorithm that retrieves related results from the search index. Your query's results are displayed on a search engine results page, or SER.



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