Could anyone advice on how do I improve the performance of the following query. Note, the problem seems to be caused by where clause. Data (table contains a huge set of rows - 500K+, the set of pa...

Recently I found a couple of tables in a Database with no Clustered Indexes defined. But there are non-clustered indexes defined, so they are on HEAP. On analysis I found that select statements w...

Could you guys please review the following query to an Oracle DB and point out what's wrong: SELECT t1.name FROM t1, t2 WHERE t1.id = t2.id AND t2.empno IN (1, 2, 3, …, 200) Query statistics: ...

I have the following statement to find unambiguous names in my data (~1 Million entries): select Prename, Surname from person p1 where Prename is not null and Surname is not null and not exists ...

I'm currently working my way through the Microsoft SQL Server 2008 - Database Development (MCTS Exam 70-433) certification. In one of the earlier chapters on Combining Datasets, I came across the E...

I've heard that SELECT * is generally bad practice to use when writing SQL commands because it is more efficient to SELECT columns you specifically need. If I need to SELECT every column in a table...

I've experimented with a number of techniques for monitoring the health of our SQL Servers, ranging from using the Management Data Warehouse functionality built into SQL Server 2008, through other ...

Performance question ... I have a database of houses that have geolocation data (longitude & latitude). What I want to do is find the best way to store the locational data in my MySQL (v5.0.2...

I'm new to Oracle db. I have 2 queries which return the same result set. I want to measure the performance of each of them and choose the better one. How do I do that using Oracle SQL developer? I ...