adriennn
Valued Contributor

try to run the DLT pipeline with the code either as an SQL cell in a notebook or an *.sql file to see if you have the same problem:

SELECT

a.column_a as id_column,
a.column_b as val_column
FROM catalog_a.schema_a.table_a

UNION ALL

SELECT
column_a as id_column,
column_b as val_column
FROM  catalog_shema_table_b;