Learning MySQL By Example
Using the DISTINCT Statement
Removing Duplicate Values With DISTINCT
- The DISTINCT keyword allows you to eliminate duplicate rows in aggregate functions.
- You may also use the DISTINCT keyword with columns of the base table in a SELECT statement.
- COUNT(list_price) counts all the rows in the product table that have a list price.
- COUNT(DISTINCT list_price) eliminates duplicate values in the list_price.
SELECT COUNT(list_price), COUNT(DISTINCT list_price)
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