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  To calculate a running total in SQL Server, you can use the window function SUM along with the OVER clause. Here's an example of how you can do it:

  In SQL Server, you can concatenate text from multiple rows into a single text string using the FOR XML PATH('') clause. Here's an example:

A clustered index and a non-clustered index are both used to improve query performance in SQL Server, but they have some key differences: Clustered Index Non-Clustered Index Physical organization of data Determines the physical order of data in a table Separately stored data structure that contains indexed columns and a pointer to the actual table data Number of indexes per table Only one per table Multiple per table Key type Primary key or unique identifier Any column or combination of columns Index key order Dictates the physical order of the data in the table Does not dictate physical order of the data Additional columns All columns are included in the index Can include additional columns beyond the indexed columns Performance Generally faster for range queries and ordered data Generally faster for specific value queries and unordered data Storage space Uses less storage space than non-clustered indexes Uses more storage space than clustered indexes Maintenance May require more main

  In SQL Server, there are three types of index configurations that can be applied to a table: Clustered Index : A clustered index determines the physical order of data in a table, and there can be only one clustered index per table. The index key of a clustered index is used as the primary key of the table, or if no primary key is defined, a unique identifier is created. When data is retrieved from a table with a clustered index, it is read in the order of the index key, which can improve performance for range queries and ordered data. Non-Clustered Index : A non-clustered index is a separate data structure that contains the indexed columns and a pointer to the actual table data. Multiple non-clustered indexes can be created on a table, and they are useful for optimizing queries that search for specific values in columns that are not part of the clustered index. Non-clustered indexes can also include additional columns beyond the indexed columns, which can help to cover certain querie

  By default, SQL Server uses TCP/IP port 1433 for communication over the network. However, this default port can be changed during installation or later configuration of the SQL Server instance. It's important to note that if a named instance of SQL Server is used, a dynamic port may be assigned to that instance, which means the port number could be different. To find out which port a particular SQL Server instance is listening on, you can use SQL Server Configuration Manager or run the following query against the instance: sql SELECT DISTINCT local_tcp_port FROM sys.dm_exec_connections WHERE local_tcp_port IS NOT NULL This will return the port number on which the SQL Server instance is currently listening for TCP/IP connections.

Photo by David Selbert : https://www.pexels.com/photo/squirrel-eating-cone-in-forest-8797307/ To get a list of all tables in your SQL Server database, you can query the sys.tables system catalog view. Here's how to do it: sql SELECT name FROM sys.tables; This will return a list of all tables in the current database. If you want to get more information about the tables, you can use the following query: sql SELECT name, create_date, modify_date FROM sys.tables; This will return the table name, creation date, and last modification date for each table in the database. Note that if you are connected to a different database, you will need to use the USE statement to switch to the desired database before running the query. For example: sql USE mydatabase; SELECT name FROM sys.tables;

  To limit the number of rows returned by a query after ordering in SQL Server, you can use the "TOP" clause in your query. This clause specifies the number of rows that should be returned from the result set after sorting. Here's an example query: sql SELECT TOP 10 column1, column2, column3 FROM your_table ORDER BY column1; In this example, the query will return the first 10 rows of the result set after sorting by "column1". You can adjust the number of rows returned by changing the number after the "TOP" keyword. If you want to return a percentage of the rows, you can use the "TOP" keyword followed by a percentage value, like this: sql SELECT TOP 10 PERCENT column1, column2, column3 FROM your_table ORDER BY column1; This query will return the top 10% of the rows in the result set after sorting by "column1". You can adjust the percentage by changing the value after the "TOP" keyword.