gaps-and-islands

I have an application that may be run several times a day. Each run results in data that is written to a table to report on events that occurred. The main report table looks something like this: Id SourceId SourceType DateCreated 5048 433 FILE 5/17/2011 9:14:12 AM 5049 346 FILE 5/17/2011 9:14:22 AM 5050 444 FILE 5/17/2011 9:14:51 AM 5051 279 FILE 5/17/2011 9:15:02 AM 5052 433 FILE 5/17/2011 12:34:12 AM 5053 346 FILE 5/17/2011 12:34:22 AM 5054 444 FILE 5/17/2011 12:34:51 AM 5055 279 FILE 5/17/2011 12:35:02 AM I can tell that there were two runs, but I would like a way to be able to query for a

I have tried several topics like this one: How to find missing data rows using SQL? here, but I couldn't make it work in my situation. I have a table named posts in MySQL which I save user diaries in it every day. Sometimes users forget to write a post for a day and I want to make it possible for them to submit it later. So the db structures like this: date userid 2011-10-01 1 2011-10-02 1 (missing) 2011-10-04 1 2011-10-05 1 (missing) 2011-10-07 1 So I want to show a dropdown list of missing dates in this table of missing rows to user, so he can select the date he wants to submit the post for.

Given the following table: ID State Date 12 1 2009-07-16 10:00 45 2 2009-07-16 13:00 67 2 2009-07-16 14:40 77 1 2009-07-16 15:00 89 1 2009-07-16 15:30 99 1 2009-07-16 16:00 Question: How can i GROUP by the field "State", while still maintaining the borders between the state changes? SELECT MIN(ID) AS ID, State, MIN(Date) AS Date, COUNT(ID) AS Count FROM table GROUP BY State results in the following: ID State Date Count 12 1 2009-07-16 10:00 4 45 2 2009-07-16 13:00 2 but this is expected: ID State Date Count 12 1 2009-07-16 10:00 1 45 2 2009-07-16 13:00 2 77 1 2009-07-16 15:00 3 Is this

I have a set of transactions occurring at specific points in time: CREATE TABLE Transactions ( TransactionDate Date NOT NULL, TransactionValue Integer NOT NULL ) The data might be: INSERT INTO Transactions (TransactionDate, TransactionValue) VALUES ('1/1/2009', 1) INSERT INTO Transactions (TransactionDate, TransactionValue) VALUES ('3/1/2009', 2) INSERT INTO Transactions (TransactionDate, TransactionValue) VALUES ('6/1/2009', 3) Assuming that the TransactionValue sets some kind of level, I need to know what the level was between the transactions. I need this in the context of a set of T-SQL

I manage a message based system in which a sequence of unique integer ids will be entirely represented at the end of the day, though they will not necessarily arrive in order. I am looking for help in finding missing ids in this series using SQL. If my column values are something like the below, how can I find which ids I am missing in this sequence, in this case 6 ? The sequence will begin and end at an arbitrary point each day, so min and max would differ upon each run. Coming from a Perl background I through some regex in there. ids 1 2 3 5 4 7 9 8 10 Help would be much appreciated. Edit:

Not using MSSQL or DB2 or Oracle. No CTE. No OVERLAP predicate. No INTERVAL data type. The situation: on a vehicle to be repaired work can not start until all parts ordered for the job have been received. Parts may be ordered multiple times prior to the start of repair. We need to extract the time for which the vehicle was on "parts hold" So for a vehicle identified as id = 1 parts were ordered (d1) and received (d2) on 4 different occasions ID d1 d2 1 8/1 8/8 1 8/2 8/6 1 8/12 8/14 1 8/3 8/10 8/1 8/8 d1 d2 |-------------------------------| 8/2 8/6 8/12 8/14 d1 d2 d1 d2 |---------------| |-----