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T SQL Table Variable

SQL Server TSQL Table Variables

Table Variables In SQL Server: These tables behave very much like other variables in their scoping rules. They are created when they are declared and are dropped when they go out of scope. They cannot be explicitly dropped. Like with temp tables, table variables also reside in TempDB. They are also generally accessed only from memory, unless the server is under memory pressure or the amount of data in the table is large.

Table variables can have a primary key, but no indexes can be created on them. They don’t have any statistics maintained on the columns. This makes table variables less optimal for large numbers of rows, as the … Read the rest

SQL Server TSQL Temporary Table

Temp tables in SQL Server: they are just like any normal tables except that they are created in the TempDB database. They persist until dropped, or until the connection that created them disappears. They are visible in the procedure that created them and any procedures that it calls. Just like normal tables and have primary keys, constraints, indexes and column statistics which are kept for the table which makes query execution really fast in most cases. Temp tables can be created in all versions of SQL Server including SQL Server Express Edition.

Temp tables have space assigned to them in the TempDB database and are generally accessed only from memory, unless the server is under … Read the rest