SQL - Structured Query Language For database analyses SQL – Structured Query Language • SQL is designed to do variable selection and manipulation on data stored in multiple tables Why multiple tables? (aka database) • Avoid duplication of information • Ease of updating information • Linked by unique identifiers/codes Where would we use? A single entity with many different operations with common information University • Many functions: students taking classes & getting grades, scheduling classes in rooms, students paying tuition & fees, faculty teaching classes, faculty getting paid, etc Tables of • Students, faculty with demographics • Students*classes, faculty*classes • Tuition payments, faculty payroll, etc. • Linked by studentID, facultyID, classID, etc Business • Multiple functions including selling, buying, production, and paying employees Tables of orders, suppliers, customers, products, accounts payable & receivable, payroll, …. Linked by productID, customerID, … Baseball Lahman database – season summaries • Tables of teams, batting (player*season), pitching (player*season), salaries, demographics (Master) • Linked by playerID, teamID, etc. • Why baseball? Nonproprietary, not small, interesting? … maybe In SAS • PROC SQL • Designed to run interactively (end with QUIT;) • Tables are stored as SAS datasets Let’s look at the baseball data in SAS….
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