sql-limit

Given that I've got a table with the following, very simple content: # select * from messages; id | verbosity ----+----------- 1 | 20 2 | 20 3 | 20 4 | 30 5 | 100 (5 rows) I would like to select N messages, which sum of verbosity is lower than Y (for testing purposes let's say it should be 70, then correct results will be messages with id 1,2,3). It's really important to me, that solution should be database independent (it should work at least on Postgres and SQLite). I was trying with something like: SELECT * FROM messages GROUP BY id HAVING SUM(verbosity) < 70; However it doesn't seem to

I am trying to limit the following SQL statement. SELECT expense.*, transaction.* FROM expense INNER JOIN transaction ON expense_id = transaction_expense_id What I want to do, is limit the number of 'parent' rows. IE. if I do a LIMIT 1, I would receive only one expense item, but still get all transactions associated with it. How would this be achieved? At this stage, if I do LIMIT 1, I get one expense, and only one transaction. So assuming we can exclude the user table, it could be rewritten as: select * from expense, transaction where expense_id = transaction_expense_id Now if you want to

What I want to do is SUM a column, but also COUNT the number of rows it is summing, with a limit of no more than 5 rows. So my query is: SELECT COUNT(*), SUM(score) FROM answers WHERE user=1 LIMIT 5 What I expected back was a COUNT(*) up to 5 (I cant just assume it will always be 5 in my code logic as it could have less than 5 answers), with a sum of the score of the up to 5 rows. Instead what I seem to get back is the total number of matching rows (where user is 1) as the count, and the sum of the score for those rows. The numbers don't change whether I put LIMIT 1 or LIMIT 5 or even LIMIT 50

I am developing a Java Web service allow paging when fetching big data set from a DB2 Database on a IBM Mid Range Machine (AS400). For example; if there are 10000 records in a data set, I want to fetch them in 1000 blocks at a time. I found this article that explains that I can use LIMIT, and OFFSET. But I need to set the DB2_COMPATIBILITY_VECTOR variable to MYS . Now I have been googling and saw you can use the db2set to set this variable. But I have not been able to find out where to type this command in? I am developing on a windows machine, and I have the iSeries installed, and I have

I am testing my database design under load and I need to retrieve only a fixed number of rows (5000) I can specify a LIMIT to achieve this, however it seems that the query builds the result set of all rows that match and then returns only the number of rows specified in the limit. Is that how it is implemented? Is there a for MySQL to read one row, read another one and basically stop when it retrieves the 5000th matching row? MySQL is smart in that if you specify a LIMIT 5000 in your query, and it is possible to produce that result without generating the whole result set first, then it will

SELECT name FROM mydb ORDER BY score DESC LIMIT 10; The query above will return the first 10 ranks. How to modify the LIMIT , or maybe is there another syntax to query the 10th rank through the 20th rank? James C This is really basic stuff. You should use: SELECT name FROM mydb ORDER BY score DESC LIMIT 10,10; http://dev.mysql.com/doc/refman/5.5/en/select.html The two arguments 10,10 are (Offset, Limit) so this will retrieve rows 11-20. 9,11 Would be required to grab the 10th - 20th rank. Use offset to clarify the query. SELECT name FROM mydb ORDER BY score DESC LIMIT 10 OFFSET 10 Limit has