Author: sqltutorial_wmkd8s

A Common Table Expression (CTE) is a temporary result set in a SELECT, INSERT, UPDATE, or DELETE statement that you can reference within the context of another SQL statement. CTEs provide a way to define complex queries and make SQL code more readable and modular. Here’s a breakdown of the key components and usage of…(Continue Reading)

Deleting duplicate rows in a database table is a common task in SQL, and it’s important for maintaining data integrity. Duplicate rows can occur for various reasons, such as data entry errors or system glitches. Here’s a guide on how to delete duplicate rows in SQL: Identifying Duplicate Rows Before deleting duplicate rows, you need…(Continue Reading)

In SQL, string matching refers to the process of finding and retrieving data from a database based on specific patterns or conditions within character strings. SQL provides various tools and functions to perform string matching operations, allowing users to search for specific substrings, patterns, or values within text columns. Here are some common techniques and…(Continue Reading)

In SQL Server, escaping apostrophes is an important consideration when dealing with string literals to ensure the proper handling of single quotes within the text. The single quote character is used to delimit string literals in SQL, so if your string contains a single quote, you need to escape it to avoid syntax errors or…(Continue Reading)

In SQL(SQL Server database), both COALESCE and ISNULL are used to handle NULL values in expressions and queries, providing a way to return a non-NULL alternative if the original value is NULL. However, there are some differences between the two functions. ISNULL Function The ISNULL function is a built-in SQL Server function that replaces NULL…(Continue Reading)

The ISNUMERIC function in SQL Server is a built-in function that is used to determine whether an expression can be evaluated as a numeric data type. It returns 1 if the expression can be converted to a numeric type; otherwise, it returns 0. The ISNUMERIC function is often employed in scenarios where you need to…(Continue Reading)

The SQL Server IIF function is a logical function introduced in SQL Server 2012 (Transact-SQL). It stands for “Immediate IF” and provides a more concise way to write a simple CASE statement with two possible outcomes. Syntax The syntax of the IIF function is as follows: IIF (boolean_expression, true_value, false_value) boolean_expression: This is the condition…(Continue Reading)

In SQL Server, the ISNULL function is used to replace NULL values with a specified replacement value. It is a convenient way to handle NULLs in SQL queries and expressions. The ISNULL function takes two parameters—the expression to be checked for NULL and the value to be returned if the expression is NULL. Syntax Here…(Continue Reading)

In SQL, concatenating strings involves combining two or more string values into a single string. This can be useful in various scenarios, such as creating a full name by combining a first name and a last name, or constructing dynamic SQL queries. SQL provides several ways to concatenate strings, and the choice of method may…(Continue Reading)

The SQL CONCAT_WS function is used to concatenate values from multiple columns or expressions with a specified separator. The name CONCAT_WS stands for “Concatenate With Separator.” This function is particularly useful when you want to combine the values of multiple columns or expressions into a single string, and you want to include a separator between…(Continue Reading)