Each query provides a unique set of data, presumably with different fields/columns, so I'm not sure you want to combine multiple queries into a single input. Defining multiple inputs allows you flexibility in scheduling and in determining other parameters like source type and field names.
If you really need to combine output from multiple queries that would have common field names, etc., you could use a UNION type of construct to combine their data sets into a single set for return to Splunk. I'm not sure what the exact Informix syntax would be, but perhaps something like this:
select column_1, column_2 from table_1 where column_1 = x
union
select column_1, column_2 from table_2 where column_2 = y
or like this:
with query_1 as
(select column_1, column_2 from table_1 where column_1 = x
union
select column_1, column_2 from table_2 where column_2 = y)
select column_1, column_2 from query_1
or perhaps combine the queries into a view in the database and select from the view in your input.
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