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MySQL Tutorial - Group Functions with Non-group Selections
(Continued from previous topic...)
Can Group Functions Be Mixed with Non-group Selection Fields?
If a group function is used in the SELECT clause, all other selection fields
must be group level fields. Non-group fields can not be mixed with group fields
in the SELECT clause. The script below gives you an example of invalid SELECT statements
with group and non-group selection fields:
mysql> SELECT COUNT(*), url FROM fyi_links;
ERROR 1140 (42000): Mixing of GROUP columns
(MIN(),MAX(),COUNT(),...) with no GROUP columns
is illegal if there is no GROUP BY clause
In this example, COUNT(*) is a group field and "url" is a non-group field.
(Continued on next topic...)
- What Is a SELECT Query Statement?
- How To Create a Testing Table with Test Data?
- How To Select All Columns of All Rows from a Table?
- How To Select Some Columns from a Table?
- How To Select Some Rows from a Table?
- How To Add More Data to the Testing Table?
- How To Sort the Query Output?
- Can the Query Output Be Sorted by Multiple Columns?
- How To Sort Output in Descending Order?
- How To Use SELECT Statement to Count Number of Rows?
- Can SELECT Statements Be Used on Views?
- How To Filter Out Duplications in Returning Rows?
- What Are Group Functions?
- How To Use Group Functions in the SELECT Clause?
- Can Group Functions Be Mixed with Non-group Selection Fields?
- How To Divide Query Output into Groups?
- How To Apply Filtering Criteria at Group Level?
- How To Count Duplicated Values in a Column?
- Can Multiple Columns Be Used in GROUP BY?
- Can Group Functions Be Used in the ORDER BY Clause?