Category: SQL

A subquery in SQL is a query that is nested within another query. It is used to retrieve data that will be used in the main query as a filter condition, or as a source of data for a calculation. The SQL subqueries are used to retrieve data that will be used as a condition…(Continue Reading)

SQL NULLIF is a function that is used to compare two expressions and return NULL if they are equal. It is a very useful function in SQL, especially when you are dealing with data that may contain empty or null values. Syntax The syntax for NULLIF is: NULLIF(expression1, expression2) The function compares expression1 with expression2.…(Continue Reading)

SQL COALESCE is a useful function that returns the first non-null value from a list of expressions. It takes any number of expressions as arguments, and returns the first non-null expression. If all expressions evaluate to null, then it returns null. Syntax The syntax of the COALESCE function is as follows: COALESCE(expression1, expression2, expression3, …)…(Continue Reading)

The SQL CASE statement is a powerful tool that allows you to perform conditional logic in your SQL queries. The statement is used to evaluate a condition or set of conditions and return a value based on the result of that evaluation. Syntax The basic syntax of the SQL CASE statement is as follows: CASE…(Continue Reading)

The SQL XML data type is a data type that allows for the storage and manipulation of XML data within a relational database management system (RDBMS). XML, or Extensible Markup Language, is a format for representing and exchanging structured data on the web. By using the SQL XML data type, developers can store and retrieve…(Continue Reading)

SQL IMAGE data type is a data type used in SQL Server to store binary data in the form of images. The IMAGE data type is a variable-length binary data type that can store up to 2^31-1 bytes of data. The IMAGE data type is deprecated in SQL Server 2005 and later versions, and Microsoft…(Continue Reading)

In SQL, the VARBINARY data type is used to store binary data in a variable-length format. It is similar to the VARCHAR data type, but instead of storing character strings, it stores binary data such as images, audio files, or other non-textual data. The VARBINARY data type can be used to store data in the…(Continue Reading)

In SQL, the BINARY data type is used to store binary data in a fixed-length format. Binary data is data that is composed of only 0s and 1s, such as machine code or encrypted data. The BINARY data type is similar to the VARBINARY data type, which is used to store variable-length binary data. However,…(Continue Reading)

SQL DATETIME2 is a date and time data type in SQL Server that was introduced in SQL Server 2008. It offers greater precision and a larger range of values than the DATETIME data type, making it a better choice for applications that require precise time measurement. Syntax The syntax for declaring a column of type…(Continue Reading)

In SQL, the DATETIME data type is used to represent date and time values. It is a composite data type that combines the DATE and TIME data types. The DATETIME data type is commonly used in database systems to store and manipulate time-related data, such as timestamps of when a particular event occurred. The SQL…(Continue Reading)