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From ton80 <mell...@nc.rr.com>
Subject Checking A ResultSet
Date Fri, 13 Feb 2009 21:48:48 GMT

Hi Forum,

I am working with an embedded derby DB.
I have a query that will total a column from a table (bigDecimal values) and
cast the result to a string.  Then return that value.  All works well if
there is at least one row in the table that meets the query requirements. 
However, if there are no rows...I get a null pointer error.

I am using
if (resultset.next()) {
do something with the result set
}

Is there a way to to check this that I need to do?

Here is the code in question...

protected String getSalesTotals(String tableName, String method) {
		String strTotal = null;
		ResultSet rs = null;
		PreparedStatement psTotal = null;
		
		try {
			if (method.equals("All")) {
				psTotal =
					conn.prepareStatement("select sum(AMT_PAID) from " + tableName + "
where TRANS_DATE=?");
				psTotal.setDate(1, new java.sql.Date(new Date().getTime()));
				rs = psTotal.executeQuery();
			}
			else {
				psTotal = conn.prepareStatement("select sum(AMT_PAID) from " + tableName
+ " where TRANS_DATE=? and PAYMENT_METH=?");
				psTotal.setDate(1, new java.sql.Date(new Date().getTime()));
				psTotal.setString(2, method);
				rs = psTotal.executeQuery();
			}
		}
		catch (SQLException e) {
			e.printStackTrace();
		}
		
		
		try {
			if (rs.next()) {
				strTotal = rs.getBigDecimal(1).toString();
			}
		}
		catch (SQLException e) {
			e.printStackTrace();
		}
		
		return strTotal;
	}

Any and all pointers, advice, and assistance is greatly appreciated.
Mike

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