java - Queries returning multiple result sets

Question

I have a MSSQL database and am running the following query:

select * from projects; select * from user

The above query returns two result sets at once, and I cannot fire both queries separately. How can I handle both the result set at once in a Java class?

Answer 1

Correct code to process multiple ResultSets returned by a JDBC statement:

PreparedStatement stmt = ...;
boolean isResultSet = stmt.execute();

int count = 0;
while(true) {
    if(isResultSet) {
        rs = stmt.getResultSet();
        while(rs.next()) {
            processEachRow(rs);
        }

        rs.close();
    } else {
        if(stmt.getUpdateCount() == -1) {
            break;
        }

        log.info("Result {} is just a count: {}", count, stmt.getUpdateCount());
    }

    count ++;
    isResultSet = stmt.getMoreResults();
}

Important bits:

• getMoreResults() and execute() return false to indicate that the result of the statement is just a number and not a ResultSet.
• You need to check stmt.getUpdateCount() == -1 to know if there are more results.
• Make sure you either close the result sets or use stmt.getMoreResults(Statement.CLOSE_CURRENT_RESULT)