Table operators accept a table or table expression as input and generate a table as output. They are a type of user-defined function (UDF). Table operators are used only in the FROM clause of SELECT statements.
Scalar sub-queries (SSQ) are sub-queries that result in a single value. SSQ is not supported in table operators with multiple ON clauses or ON clauses using PARTITION BY or HASH BY.
For information on the LOAD_FROM_HCATALOG table operator, see Teradata QueryGrid: Teradata Database-to-Hadoop.