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Does select distinct take longer?
Very few queries may perform faster in SELECT DISTINCT mode, and very few will perform slower (but not significantly slower) in SELECT DISTINCT mode but for the later case it is likely that the application may need to examine the duplicate cases, which shifts the performance and complexity burden to the application.
How can I speed up a distinct query?
You probably don’t want to hear this, but the best option to speed up SELECT DISTINCT is to avoid DISTINCT to begin with. In many cases (not all!) it can be avoided with better database-design or better queries. Sometimes, GROUP BY is faster, because it takes a different code path.
Does distinct make query slow?
Running with the DISTINCT keyword If you do, your phone will ring, your pager will go vibrate, your users will have a hard time forgiving you, and performance will slow to a crawl for a little while. A quick examination of the query plan reveals that a table scan is still being used to retrieve the data from the table.
How to fix SQL Server query taking too long?
Either you can kill that session or commit the transaction in it. For me disconnecting the SQl database and reconnecting it back helped to solve the problem. The problem was while updating a table (few transactions have been triggered/ they need commit).
How long does it take to select data from table?
The selection of data from table is taking more than 20 sec to retrieve close to 300k records. Created a clustered index on col1 and col2 but no improvement. Created indexes on col1 and col2 but col3 data is very big, more than 8000 characters, so SQL-server will not allow index on such column.
Can a column be too big for an index key?
For the columns that are normally too large for an index key, you may be able to gain some benefits of indexing by including them in an index. Use the Query as below, Thanks for contributing an answer to Database Administrators Stack Exchange! Please be sure to answer the question.