For a multiple libref join to pass to SAP ASE, all of these components of the LIBNAME statements must match exactly:
SAP ASE supports nonstandard outer-join syntax. Outer joins between two or more tables can be passed to SQP ASE with these restrictions:
For all queries that use an ON clause, both operands in the ON clause must reference a column name. Literal operands cannot be passed down to the DBMS. Because literal operands are not supported, all ON clauses are transformed into WHERE clauses before passing joins down to the DBMS. This can result in a query not being passed down if it contains additional WHERE clauses or if it contains complex join conditions.
SAP ASE evaluates multijoins that have WHERE clauses differently than SAS. Therefore, instead of passing multiple joins or joins that have additional WHERE clauses to SAP ASE, use the DIRECT_SQL= LIBNAME option to let PROC SQL process the join internally.
For more information about when and how SAS/ACCESS passes joins to the DBMS, see Passing Joins to the DBMS.