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Aggregate Functions

   A scalar function in SQL is a type of function that operates on individual values, returning a single result for each input value. Unlike aggregate functions, which operate on sets of values and return a single result for the entire set, scalar functions work on each row independently. These functions can perform various operations such as string manipulation, mathematical calculations, date/time operations, and type conversion. Scalar functions are commonly used within SELECT statements, WHERE clauses, and expressions to transform or manipulate data on a row-by-row basis.

 

  1. String Functions:
    • CONCAT: Concatenates two or more strings.
    • SUBSTRING: Extracts a substring from a string.
    • UPPER/UCASE: Converts a string to uppercase.
    • LOWER/LCASE: Converts a string to lowercase.
    • TRIM: Removes leading and trailing spaces from a string.
    • LENGTH/LEN: Returns the length of a string.

 

  1. Numeric Functions:
    • ABS: Returns the absolute value of a number.
    • ROUND: Rounds a number to a specified number of decimal places.
    • CEILING: Rounds a number up to the nearest integer.
    • FLOOR: Rounds a number down to the nearest integer.
    • SQRT: Returns the square root of a number.

 

  1. Date and Time Functions:
    • DATEADD: Adds a specified time interval to a date.
    • DATEDIFF: Calculates the difference between two dates.
    • DATEPART: Returns a specific part of a date (e.g., year, month, day).
    • GETDATE/NOW: Returns the current date and time.
    • DATE_FORMAT: Formats a date according to a specified format.

 

  1. Conversion Functions:
    • CAST/CONVERT: Converts a value from one data type to another.
    • COALESCE: Returns the first non-null value in a list of expressions.

 

  1. Mathematical Functions:
    • SIN, COS, TAN: Trigonometric functions.
    • LOG, LOG10, EXP: Logarithmic functions.

 

These functions can be used in SQL queries to perform various operations on data, depending on the specific requirements of the task at hand.

 


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