MySQL 5.1 with Maria Reference Manual :: 3 Tutorial :: 3.6 Examples of Common Queries :: 3.6.3 Maximum of Column per Group
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- 3.6 Examples of Common Queries
- 3.6.1 The Maximum Value for a Column
- 3.6.2 The Row Holding the Maximum of a Certain Column
- 3.6.3 Maximum of Column per Group
- 3.6.4 The Rows Holding the Group-wise Maximum of a Certain Column
- 3.6.5 Using User-Defined Variables
- 3.6.6 Using Foreign Keys
- 3.6.7 Searching on Two Keys
- 3.6.8 Calculating Visits Per Day
- 3.6.9 Using AUTO_INCREMENT
Task: Find the highest price per article.
SELECT article, MAX(price) AS price FROM shop GROUP BY article; +---------+-------+ | article | price | +---------+-------+ | 0001 | 3.99 | | 0002 | 10.99 | | 0003 | 1.69 | | 0004 | 19.95 | +---------+-------+
User Comments
There seems to be no NULL=Infinity maximum version. In a column is stored end (type date) with NULL = no end. I need the maximum of that column, which is NULL if a NULL-value exists. That should be easy to implement as a function, but not so easy with the existing function.
The same for sum, avg and so on. The versions with NULL=ignore are usefull most of the time, but sum() of NULL and 5 can sometimes be NULL instead of 5. NULL+5 is NULL.
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