Designer is not aware of the system schema "SYSADMIN"

SELECT
a.*, b.TablesUsed, b.isPhysical
FROM
(SELECT DISTINCT ((x.SchemaName || '.') || x.Name) AS FQN_Object, ((x.Uses_schemaName || '.') || x.Uses_Name) AS tablesUsed, y.isPhysical FROM SYSADMIN.Usage AS x, SYS.Schemas AS y WHERE (y.name = x.SchemaName) AND (x.schemaName NOT IN ('SYS', 'SYSADMIN')) ORDER BY ((x.SchemaName || '.') || x.Name)) AS a LEFT OUTER JOIN (SELECT DISTINCT ((x.SchemaName || '.') || x.Name) AS FQN_Object, ((x.Uses_schemaName || '.') || x.Uses_Name) AS tablesUsed, y.isPhysical FROM SYSADMIN.Usage AS x, SYS.Schemas AS y WHERE (y.Name = x.SchemaName) AND (x.schemaName NOT IN ('SYS', 'SYSADMIN')) ORDER BY ((x.SchemaName || '.') || x.Name)) AS B ON a.TablesUsed = b.FQN_Object

Results in

ERROR: Group does not exist: SYSADMIN.Usage AS x