InterSystems MDX Reference MAX

Returns the maximum value of a given expression (or of the current measure), across all elements of a set.
Returned Type
This function returns a number.
Syntax and Details
`MAX(set_expression, optional_numeric_expression)`
Where:
The function evaluates the numeric value for each element of the set and returns the largest of those values.
Example
First, the following query shows values of three measures for the members of the aged.decade level:
```SELECT {MEASURES.[%COUNT],MEASURES.[encounter count],MEASURES.[avg test score]} ON 0,
Patient Count    Encounter Count     Avg Test Score
1 1910s                         80              5,359              75.17
2 1920s                        227             12,910              74.20
3 1930s                        567             33,211              74.67
4 1940s                        724             38,420              73.39
5 1950s                      1,079             46,883              73.72
6 1960s                      1,475             57,814              74.16
7 1970s                      1,549             49,794              74.35
8 1980s                      1,333             35,919              74.13
9 1990s                      1,426             29,219              74.79
10 2000s                      1,406             20,072              74.95
11 2010s                        134              1,346              73.55```
Next, the following query shows the maximum values for these measures for the members of this level:
```SELECT {MEASURES.[%COUNT],MEASURES.[encounter count],MEASURES.[avg test score]} ON 0,
Patient Count    Encounter Count     Avg Test Score
MAX                           1,549             57,814              75.17```
Here, each value is the maximum of the values in a column in the preceding query. For example, the Patient Count value is the maximum of the Patient Count values in the preceding query.
Notice that these maximum values do not belong to the same member. For example, the decade with the highest patient count is not the same as the decade with the highest average test score.
For another example, we use the second argument for MAX:
```SELECT MAX(birthd.decade.MEMBERS, MEASURES.[%COUNT]) ON 0 FROM patients
MAX
1,549```
For additional, similar examples, see AVG.