max aggregate function
Applies to: 
Databricks SQL Databricks Runtime
Returns the maximum value of expr in a group.
Syntax
max(expr) [FILTER ( WHERE cond ) ]
This function can also be invoked as a window function using the OVER clause.
Arguments
expr: An expression of any type that can be ordered.cond: An optional boolean expression filtering the rows used for aggregation.
Returns
The result type matches the type of the argument.
note
For certain STRING collations, such as UTF8_LCASE, the result may be non-deterministic.
Examples
SQL
> SELECT max(col) FROM VALUES (10), (50), (20) AS tab(col);
50
-- The result is non-deterministic due to collation
> SELECT max(col COLLATE UTF8_LCASE) FROM VALUES ('a', 'A') AS tab(col);
a (or A)