How are count and distinct used in MySQL?

In MySQL, the COUNT() function is used to calculate the number of rows in a specified column, while the DISTINCT keyword is used to specify counting only unique values. Typically, the COUNT() function will count all rows including duplicate values, whereas the DISTINCT keyword can ensure counting only distinct values.

For example, if you want to count the number of unique values in a column of a table, you can use the following statement:

SELECT COUNT(DISTINCT column_name) FROM table_name;

This will count the number of distinct values in that column.

Additionally, the COUNT() function can also be used in conjunction with other conditions, such as:

SELECT COUNT(DISTINCT column_name) FROM table_name WHERE condition;

This will count the number of unique values in that column that meet the criteria.