Agreement Function in SQL: An Overview
Structured Query Language or SQL is a programming language used for managing data in Relational Database Management Systems. SQL has a wide variety of functions to manipulate and extract data from databases. Among these functions is the Agreement Function, which is used to retrieve the maximum or minimum value from a set of values.
The syntax of the Agreement Function is quite simple. It takes in a set of values and returns the maximum or minimum value from that set. The following is the general syntax for the Agreement Function in SQL:
AGGREGATE_FUNCTION (DISTINCT/ALL expression)
Here, the AGGREGATE_FUNCTION is the Agreement Function (MAX or MIN), and expression is the column or expression that we want to evaluate.
Let`s take a closer look at how we can use the Agreement Function in SQL.
Using the MAX Function
The MAX Function is used to retrieve the maximum value from a set of values. It is often used in SQL queries to find the highest value in a column or set of columns.
Consider the following table:
| ID | Name | Age |
| — | —- | — |
| 1 | John | 23 |
| 2 | Jane | 26 |
| 3 | Mary | 22 |
| 4 | Mark | 30 |
To find the highest age in this table, we can use the following SQL query:
SELECT MAX(Age) FROM table_name;
This query will return the value 30, which is the highest age in the table.
Using the MIN Function
The MIN Function is used to retrieve the minimum value from a set of values. It is similar to the MAX Function, but instead of returning the highest value, it returns the lowest value.
Consider the same table as above. To find the lowest age in this table, we can use the following SQL query:
SELECT MIN(Age) FROM table_name;
This query will return the value 22, which is the lowest age in the table.
Using the DISTINCT Keyword
By default, the Agreement Function considers all values in the set of values. However, we can use the DISTINCT keyword to make sure that only distinct values are taken into consideration.
Consider the following table:
| ID | Name | Age |
| — | —- | — |
| 1 | John | 23 |
| 2 | Jane | 26 |
| 3 | Mary | 22 |
| 4 | Mark | 30 |
| 5 | John | 25 |
To find the distinct highest age in this table, we can use the following SQL query:
SELECT MAX(DISTINCT Age) FROM table_name;
This query will return the value 30, which is the distinct highest age in the table.
Conclusion
The Agreement Function in SQL is a powerful tool for retrieving the maximum or minimum value from a set of values. By using the MAX or MIN function, we can easily find the highest or lowest value in a column or set of columns. Moreover, by using the DISTINCT keyword, we can make sure that only distinct values are taken into consideration when evaluating the set of values. Understanding the Agreement Function and its syntax is essential for anyone working with SQL.