https://www.w3resource.com/sql/aggregate-functions/Max-with-group-by.php
entity myEntity {
key ID: Integer;
key seqNr: Integer;
key createdAt: DateTime;
...
}
@readonly
entity myEntityMaxSeqNr
as select from myEntity {
ID,
count(seqNr) as maxSeqNr: Integer
createdAt,
...
}
group by
ID,
createdAt;
This can also be done using CQL like here.
Since there is nothing in the official CAP documentation about min and max functions, I figured out the following syntax:
const result1 = await cds.run(`SELECT *, MAX(seqNr) FROM ${myTable} LIMIT 1`) //returns array
const result2 = await SELECT.one.from(myTable, [`MAX(seqNr)`]).columns('*') //returns object
const result3 = await SELECT.one.from(myTable).columns('MAX(seqNr)') //returns object containing only the max counter value
DATA(maximum) = REDUCE #( INIT max = VALUE myType( )
FOR line IN myTable
NEXT max = COND #( WHEN line-myColumn > max THEN line-myColumn
ELSE max ) ).
l_result = nmin( val1 = 10 val2 = 20 ). " = 10
l_result = nmax( val1 = 10 val2 = 20 ). " = 20