A nonclustered index in SQL Server has the same index structure as a clustered index, but doesn’t change the physical order of the rows in the table, and the leaf pages consist of an index key plus a bookmark. Learn more.
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A clustered index is built by default for each table for which you define the primary key using the primary key constraint. Learn more.
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SQL Server indices are a separate physical data structure that enables queries to access one or more data rows fast. Proper tuning of indices is key for query performance. Learn why.
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The SQL Server system base tables have the same logical structure as base tables, and you can use the same T-SQL statements to retrieve information from them as used with the base tables. Learn more.
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If you want to generate the compiled form each time a SQL Server procedure is executed, use the WITH RECOMPILE option. Learn more.
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Starting with SQL Server 2005, you can capture and handle exceptions using two statements, TRY and CATCH. Learn what “exception” means and how to use these statements.
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The main application area for the SQL Server MERGE statement is a data warehouse environment, where tables need to be refreshed periodically with new data arriving from OLTP systems. Learn more.
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The nonrecursive form of a CTE can be used as an alternative to derived tables and views. Learn how.
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Apply SQL Server derived tables when the use of column aliases is not possible because another clause is processed by the SQL translator before the alias name is known. Learn more.
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Writing a SQL Server SELECT statement using the join operator is can help the Database Engine to find a more efficient strategy for retrieving the appropriate data. Learn how.
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In SQL Server, sometimes it is necessary to retrieve, in addition to the matching rows, the unmatched rows from one or both of the tables. Such an operation is called an outer join.
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The SQL Server Database Engine sets the maximum number of tables that can be joined in a SELECT statement is 64. Learn more.
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