Query to select first row based on column with duplicates

One way:

dbadmin=> SELECT * FROM z;
 PK |  col1   | col2
----+---------+------
 A  | Hector  |  263
 A  | James   |    2
 B  | Stel    |   58
 B  | Jones   |   85
 B  | Emmons  |    3
 C  | Tobin   |   15
 D  | Dyer    |    3
 D  | Formine |    6
(8 rows)

dbadmin=> SELECT PK, col1, col2 FROM z LIMIT 1 OVER (PARTITION BY PK ORDER BY col2 DESC);
 PK |  col1   | col2
----+---------+------
 A  | Hector  |  263
 B  | Jones   |   85
 C  | Tobin   |   15
 D  | Formine |    6
(4 rows)

I'm getting an error: SQL Error [4856] [42601]: [Vertica]VJDBC ERROR: Syntax error at or near "where"

Here's my SQL:

select
"ebin added by" || "Intake ID" || Source as PK
,cast("intake id" as varchar) as IntakeID
,p.*
from ABC_PRD.abc_portal p LIMIT 1 OVER(PARTITION BY "ebin added by" || "Intake ID" || Source ORDER BY "intake id" desc)
where "Request Submit Date" >= CURRENT_DATE()-11
and (Business = 'CORE' OR Business = 'SMS')
and (Source = 'ECIN' or Source = 'Curaspan')

Put the LIMIT after the WHERE

Something like:

select
"ebin added by" || "Intake ID" || Source as PK
,cast("intake id" as varchar) as IntakeID
,p.*
from ABC_PRD.abc_portal p
where "Request Submit Date" >= CURRENT_DATE()-11
and (Business = 'CORE' OR Business = 'SMS')
and (Source = 'ECIN' or Source = 'Curaspan')
LIMIT 1 OVER(PARTITION BY "ebin added by" || "Intake ID" || Source ORDER BY "intake id" desc)