I have a database with multiple tenants with a separate schema for each tenant. The structure of each schema is identical, the tenant ID is the name of the schema.
What I would like to achieve is to able to query tables in all schemas at once with the tenant IDs added to the result set.
I have a similar structure and do my multi tenant queries this way.
The only problem I see is that we have to define every result type, because I return a record, but it runs fine.
create function sql_per_tenant(sql text, tenants text[]) returns setof record language plpgsql AS $function$ declare Result record; schemas text; begin for schemas in select unnest(tenants) loop execute Format('set local search_path to %s, public;', schemas); for Result in execute Format('select $$%1$s$$ tenant, * from (%2$s) x', schemas, sql) loop return next Result; end loop; end loop; end;$function$;
select * from sql_per_tenant('select Order_ID, sum(Value) from Orders inner join Items using(Order_ID)
where Due_Date = Current_Date','{cus_001,cus_035,cus_175}')
as (SchemaName text, Order_ID integer, sum_of_items Numeric)
