In most scenarios when working with data, users do not require all the data in each instance of a query. T-SQL (and SQL of course) provide means of retrieving only part of a data set in a table or a similar structure. The WHERE, HAVING, TOP and OFFSET-FETCH clauses are used to accomplish this in different ways. Read More
Statistics comprises lightweight objects that are used by SQL Server Query optimizer to determine the optimal way to retrieve data from the table. SQL Server optimizer uses the histogram of column statistics to choose the optimal query execution plan. If a query uses a predicate which already has statistics, the query optimizer can get all the required information from the statistics to determine the optimal way to execute the query. SQL Server creates statistics in two ways:
In this article, Auto Create Statistics and Auto Update Statistics options are analyzed. They are database specific and can be configured using SQL Server management studio and T-SQL Query. Read More
In my previous article, I demonstrated:
In this article, I am going to demonstrate:
In the previous part of this article, we discussed how to import CSV files to SQL Server with the help of BULK INSERT statement. We discussed the main methodology of bulk insert process and also the details of BATCHSIZE and MAXERRORS options in scenarios. In this part, we will go through some other options (FIRE_TRIGGERS, CHECK_CONSTRAINTS and TABLOCK) of bulk insert process in various scenarios.
According to Wikipedia, ”A Bulk insert is a process or method provided by a database management system to load multiple rows of data into a database table.” If we adjust this explanation in accordance with the BULK INSERT statement, bulk insert allows importing external data files into SQL Server. Read More
This article is about developing a basic understanding of sqlcmd utility to run T-SQL commands directly from the command prompt without the need of SSMS (SQL Server Management Studio).
The article also highlights the importance of using a lightweight sqlcmd utility to perform some basic database tasks that would otherwise require getting connected to the database through a pre-installed database tool such as SSMS (SQL Server Management Studio) or SSDT (SQL Server Data Tools) followed by getting it ready to run SQL scripts against the desired database(s).
The sqlcmd utility can be a real time-saver for database developers and DBAs since they can straight away run the required SQL scripts from the command-line.
Using the MERGE statement, we can change data in a target table based on data in a source table. Using it, we can execute INSERT, UPDATE and DELETE on the target tables within a single query block. It joins both tables using columns, common in both tables like the primary key. Based on how column data matches, changes apply to data of target table. The following image illustrates how “MERGE” works:
