Resolution:
Description:
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When trying to execute a SQL statement with max clause, function Database.queryUsingSQL threw NullPointerException. If max clause was removed, no exception is thrown.

Environment:
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TIBCO BusinessEvents - 4.x
OS - All

Symptoms:
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1). Using DB Concepts and invoking method " Database.queryUsingSQL".

2). If the SQL statement has MAX function, NullPointerException is generated. If same SQL statement is used without MAX function, it executes successfully.

Cause:
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Database.queryUsingSQL is a RDBMS function. It queries DB unlike BQL queries which are for querying cache. This function returns a Concept resultset (Concept[]) instead of certain column set. It is not possible to cast the max(column) to a Concept so it throws the NullPointerException.

Resolution:
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To get the maximum value of a column, change the SQL statement by adding a max clause in the where clause. This selects the Concepts which has the maximum value of a specific column from the target table.

Database.queryUsingSQL throws NullPointerException when the SQL statement has max clause.