Cross Join
The CROSS JOIN joined every row from the first table (T1) with every row from the second table (T2). In other words, the cross join returns a Cartesian product of rows from both tables. In general, if the first table has n rows and the second table has m rows, the cross join will result in n... » read more
SQL to Open XML file
SQL to retrieve content of xml file.
Gathering SQL Server Index Statistics and Usage Information
After creating the indexes, we should proactively know which indexes are badly used, or totally unused in order to perform the correct decision to maintain these indexes or replace it with more efficient ones. Recall that removing the unused indexes or badly indexes will improve the performance of the data modification queries, that needs to... » read more
Fine Tuning Queries
Database administrators have to balance between creating too many indexes and too few indexes. For example, there is no need to index every column individually or involve the column in many overlapping indexes. They should also take into consideration that, the index that will enhance the performance of SELECT queries will also slow down the... » read more
SQL Server Non-Clustered Index Design
A Non-clustered index is built using the same 8K-page B-tree structure that is used to build a Clustered index, except that the data and the Non-clustered index are stored separately. A Non-clustered index is different from a Clustered index in that, the underlying table rows will not be stored and sorted based on the Non-clustered... » read more
SQL Server Clustered Index Design
The clustered index can be beneficial for the queries that read large result sets of ordered sequential data. In this case, the SQL Server Engine will locate the row with the first requested value using the clustered index, and continue sequentially to retrieve the rest of rows that are physically adjacent within the index pages with the correct... » read more