Joe Celko's SQL Puzzles and Answers

Joe Celko served 10 years on ANSI/ISO SQL Standards Committee and contributed to the SQL-89 and SQL-92 Standards. Mr. Celko is author a series of books on SQL and RDBMS for Elsevier/MKP. He is an independent consultant based in Austin, Texas. He has written over 1200 columns in the computer trade and academic press, mostly dealing with data and databases.

• PUZZLE 01: FISCAL YEAR TABLES PUZZLE 02: ABSENTEESPUZZLE 03: THE ANESTHESIA PUZZLEPUZZLE 04: SECURITY BADGES PUZZLE 05: ALPHA DATA PUZZLE 06: HOTEL RESERVATIONSPUZZLE 07: KEEPING A PORTFOLIO PUZZLE 08: SCHEDULING PRINTERS PUZZLE 09: AVAILABLE SEATS PUZZLE PUZZLE 10: WAGES OF SIN:PUZZLE 11: WORK ORDER PUZZLE 12: CLAIMS STATUS PUZZLE 13: TEACHERS PUZZLE 14: TELEPHONEPUZZLE 15: FIND THE LAST TWO SALARIESPUZZLE 16: MECHANICS PUZZLE 17: EMPLOYMENT AGENCYPUZZLE 18: JUNK MAIL PUZZLE 19: TOP SALESMENPUZZLE 20: TEST RESULTSPUZZLE 21: AIRPLANES AND PILOTSPUZZLE 22: LANDLORDPUZZLE 23: MAGAZINE PUZZLE 24 ONE IN TENPUZZLE 25: MILESTONE PUZZLE 26: DATAFLOW DIAGRAMSPUZZLE 27: FINDING EQUAL SETSPUZZLE 28: CALCULATE THE SINE FUNCTION PUZZLE 29: FIND THE MODE COMPUTATION PUZZLE 30: AVERAGE SALES WAIT PUZZLE 31: BUYING ALL THE PRODUCTS PUZZLE 32: COMPUTING TAXESPUZZLE 33: COMPUTING DEPRECIATION PUZZLE 34: CONSULTANT BILLING PUZZLE 35: REQUISITIONSPUZZLE 36: DOUBLE DUTYPUZZLE 37: MOVING AVERAGE PUZZLE 38: JOURNAL UPDATING PUZZLE 39: INSURANCE LOSSES PUZZLE 40: PERMUTATIONS:PUZZLE 41: BUDGETING PUZZLE 42: COUNTING FISH PUZZLE 43: GRADUATION PUZZLE 44: PAIRS OF STYLESPUZZLE 45: PEPPERONI PIZZA PUZZLE 46: SALES PROMOTIONSPUZZLE 47: BLOCKS OF SEATS PUZZLE 48: UN-GROUPINGPUZZLE 49: WIDGET COUNTPUZZLE 50: TWO OF THREEPUZZLE 51: BUDGET VERSUS ACTUALPUZZLE 52: PERSONNEL PROBLEMPUZZLE 53: COLLAPSING A TABLE BY COLUMNSPUZZLE 54: POTENTIAL DUPLICATES PUZZLE 55: PLAYING THE PONIESPUZZLE 56: HOTEL ROOM NUMBERSPUZZLE 57: GAPS - 1 PUZZLE 58: GAPS - 2 PUZZLE 59: MERGING TIME PERIODS PUZZLE 60: BARCODES PUZZLE 61: SORTING A STRING PUZZLE 62: REPORT FORMATTING PUZZLE 63: CONTIGUOUS GROUPINGS PUZZLE 64: BOXES PUZZLE 65: AGE RANGES FOR PRODUCTSPUZZLE 66: FOUR CONSECUTIVE ABSENCES PUZZLE 67: STABLE MARRIAGES PROBLEMPUZZLE 68: CATCHING THE NEXT BUS PUZZLE 69: LIFO-FIFO INVENTORYPUZZLE 70: STOCK TRENDSPUZZLE 71: CALCULATIONS PUZZLE 72: SCHEDULING SERVICE CALLSPUZZLE 73: A LITTLE DATA SCRUBBINGPUZZLE 74: DERIVED TABLES OR NOT?PUZZLE 75: FINDING A PUB