The latter controls how long to wait for a successful connection and isn't involved in query execution. For more information, see Query time-out is not the same as connection time-out. By far, the most common reason for query time-outs is underperforming queries.
This should be the first target of your troubleshooting. Here's how to check queries:. If you observe a completed event is immediately followed by an attention event, and the duration of the completed event corresponds approximately to the time-out setting, you have identified the query. Here is an example:. The attention event having the same session ID indicates that the query was canceled by the application.
Here's an example:. Check if the CommandTimeout setting is smaller than the expected query duration. If the user's setting is correct and time-outs still occur, it's because of a query performance issue. Here's an ADO.
NET code example with a time-out value set to 10 seconds:. Query time-out is different from connection time-out or login time-out. Let's illustrate using the Adventure Works sample database. To dump the data into a new table, we add the INTO clause to the statement, as well as a name for the new table as shown with the syntax below:. In the messages window, you can see how many rows were inserted into this new table. When doing a straight SELECT from a table, the new table will have the same column names when not using column aliases and data types as the original table:.
Even the NameStyle column is the same, which uses a user defined data type. If we use expressions in the SELECT statement, the data type will be determined on-the-fly based on the expressions used. For example, let's concatenate all the names of the Person table. The length of is calculated by taking the 3 source columns — each of length 50 — together with the two spaces used in the concatenation.
You can limit the number of rows inserted in the new table. You can either use a TOP clause if it doesn't really matter which rows are inserted:. In the following example, we're only selecting rows of persons with a first name starting with the letter B. Sometimes you need to create a new table to insert data into, but there are many columns and it would take some time to type it all out manually.
By filtering out all of the data, you can still create the table without waiting! You now have the CREATE TABLE statement for your new table and you can make some adjustments, like setting the nullability of the columns, changing data types, setting a filegroup, configuring foreign and primary keys and so on. With this little trick, you can save yourself some time when creating tables.
In the previous examples, the created table was always in the same database as the source tables from the SELECT query. However, it's perfectly possible to have the destination table in another database if you specify a "three-part-name". This is database. Creating Hierarchies in PowerPivot for Excel. Retrieve file sizes from the file system using Power Query. Popular Articles. Rolling up multiple rows into a single row and column for SQL Server data.
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Searching and finding a string value in all columns in a SQL Server table. Douglas Correa is a database professional, focused on tuning, high-availability and infrastructure.
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