SQL queries

SQL (Structured Query Language) is a domain-specific language used for managing and manipulating relational databases. In SQL Server, a query is a statement or command that you use to interact with the database to retrieve, insert, update, or delete data. SQL queries are an integral part of working with SQL Server and are used for…(Continue Reading)

SQL constraints

SQL constraints are rules enforced on data columns in SQL Server databases. They ensure the accuracy and reliability of the data in the database. By restricting the type of data that can be stored in a particular column, constraints prevent invalid data entry, which is crucial for maintaining the overall quality of the database. In…(Continue Reading)


In SQL, TINYINT is a data type used to store integer values, typically representing small whole numbers. It is a compact data type that takes up very little storage space compared to larger integer types like INT or BIGINT. The TINYINT data type is primarily used when you need to conserve storage space or when…(Continue Reading)

SQL Server autoincrement

Autoincrement, also known as an identity column or auto-incrementing field, is a feature in SQL Server and many other relational database management systems (RDBMS) that simplifies the process of generating unique, sequential values for a column in a table. This feature is commonly used for primary keys, ensuring that each row in a table has…(Continue Reading)

Select rows with max value

In SQL, you can use the SELECT statement with the MAX() function to retrieve rows that have the maximum value in a specific column or set of columns. This is a common operation when you want to find the records with the highest or maximum values in a dataset. Let’s dive into how to write…(Continue Reading)


The SQL TOP clause used to limit the number of rows returned by a query. It is often used when you want to retrieve a specific number of rows from a table that meet certain criteria, or when you want to retrieve the first N rows of a result set. SQL TOP is supported by…(Continue Reading)


In SQL, the HAVING clause is used in combination with the COUNT function to filter the results of a query based on the count of rows returned by a particular condition. This clause is typically used in conjunction with the GROUP BY clause to aggregate data and then filter the aggregated results. Here’s an explanation…(Continue Reading)

SQL remove duplicates

Removing duplicates from a SQL database is a common task that can help improve data quality and query performance. Duplicates occur when there are multiple rows in a table with identical values in one or more columns. You can eliminate these duplicates using various SQL techniques and clauses. In this explanation, I’ll provide an overview…(Continue Reading)


The SQL MERGE statement stands out as a versatile tool for consolidating data from multiple sources and maintaining data integrity. It serves as a powerful alternative to the more traditional approach of using individual INSERT, UPDATE, and DELETE statements to manage data changes. The MERGE statement’s ability to handle these operations within a single statement…(Continue Reading)

SQL TCL statements

Transaction Control Language (TCL) in SQL is a subset of SQL commands used to manage database transactions. Transactions are a fundamental concept in database systems, ensuring data integrity and consistency by grouping a set of SQL statements into a single logical unit of work. TCL commands allow developers to control when changes to the database…(Continue Reading)