CSE 132A Lecture 3: L3 10/8/18
9 Oct 2018
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If condition(t1,,tm) then output in answer attributes a1,,an of t1,,tm. This naive implementation takes too long! (catastrophic) Note: we use explicit variables (m,s,etc. ) to denote tuples. Needed when using the same relation more than once in the from clause. Select all attributes using * (ex: select * - select every single schedule) Saves writing down all the attributes explicitly . Ex: retrieve all movie attributes of currently playing movies. Ex: retrieve all movies where the title starts with ta . Where title like ta% % means (cid:3247)any string(cid:3248) Ex: forgot if polanski is spelled w/ i or y . List all titles and actors of movies by fellini, in alphabetical order of titles. Specify desc for descending order or asc for ascending order, for each attribute; Aggregate functions - operate on a multiset of values of a column of a relation, and return a value. - find avg account balance at the la jolla branch.
