Apology, I don’t know Casandra. The error message indicates the row() function does not exist - which would be true unless you created a custom user row() function within the scope of your application.
I assume that the “select a,b,c from d” works without a WHERE clause, correct?
Normally a WHERE clause would identify (as you wrote it) a column “e” in table “d” and then it is compared to the value on the right side of the =.
Does “select a,b,c,e from d” work? I would hope so because the failure message indicates the row function being the failure.
Therefore what is the value of “e” that you are trying to retrieve? Maybe: where e = “Happiness” hopefully.
Given that row(0) implies you are trying to get the first row, then in Cassandra instead of the WHERE clause use the LIMIT clause as in “select a,b,c from d PER PARTITION LIMIT 1”.
Also note: for performance on large data tables, also make sure you indexed the column “e”.