SQL Functions

SQL has many built-in functions for performing calculations on data.

SQL Aggregate Functions

SQL aggregate functions return a single value, calculated from values in a column.
Useful aggregate functions:
  • AVG() - Returns the average value
  • COUNT() - Returns the number of rows
  • FIRST() - Returns the first value
  • LAST() - Returns the last value
  • MAX() - Returns the largest value
  • MIN() - Returns the smallest value
  • SUM() - Returns the sum

SQL Scalar functions

SQL scalar functions return a single value, based on the input value.
Useful scalar functions:
  • UCASE() - Converts a field to upper case
  • LCASE() - Converts a field to lower case
  • MID() - Extract characters from a text field
  • LEN() - Returns the length of a text field
  • ROUND() - Rounds a numeric field to the number of decimals specified
  • NOW() - Returns the current system date and time
  • FORMAT() - Formats how a field is to be displayed
Tip: The aggregate functions and the scalar functions will be explained in details in the next chapters.

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