prestodb/presto · error · SQLException

Value is not a number:

Error message

Value is not a number: 

What it means

Thrown by PrestoResultSet's private number-extraction helper when getObject returned a value that is neither a Number nor a Boolean, so it cannot be converted to a numeric getX (e.g. getLong/getDouble) result. The JDBC driver only coerces numeric and boolean column values; anything else (string, struct, array, map, null object) is rejected. The class name of the offending value is appended to the message.

Source

Thrown at presto-jdbc/src/main/java/com/facebook/presto/jdbc/PrestoResultSet.java:1730

        if (index == null) {
            throw new SQLException("Invalid column label: " + label);
        }
        return index;
    }

    private static Number toNumber(Object value)
            throws SQLException
    {
        if (value == null) {
            return 0;
        }
        if (value instanceof Number) {
            return (Number) value;
        }
        if (value instanceof Boolean) {
            return ((Boolean) value) ? 1 : 0;
        }
        throw new SQLException("Value is not a number: " + value.getClass().getCanonicalName());
    }

    private static List<Column> getColumns(StatementClient client, Consumer<QueryStats> progressCallback)
            throws SQLException
    {
        while (client.isRunning()) {
            QueryStatusInfo results = client.currentStatusInfo();
            progressCallback.accept(QueryStats.create(results.getId(), results.getStats()));
            List<Column> columns = results.getColumns();
            if (columns != null) {
                return columns;
            }
            client.advance();
        }

        verify(client.isFinished());
        QueryStatusInfo results = client.finalStatusInfo();
        if (results.getError() == null) {

View on GitHub (pinned to 55bb57d202)

Solutions

1. Check the column's Presto type via ResultSetMetaData.getColumnType/getColumnTypeName before calling numeric getters
2. Use getObject and convert manually for non-numeric types
3. Fix the SELECT list so the column is cast to a numeric type in SQL, e.g. CAST(col AS BIGINT)
4. Verify the column index passed to the getter points at the intended column

Example fix

// before
long v = rs.getLong(3); // column 3 is VARCHAR
// after
String s = rs.getString(3);
long v = Long.parseLong(s); // or CAST in SQL

ResultSetMetaData md = rs.getMetaData();
String type = md.getColumnTypeName(col);
boolean numeric = type.matches("(TINYINT|SMALLINT|INTEGER|BIGINT|REAL|DOUBLE|DECIMAL).*");
if (!numeric) throw new IllegalStateException("Column " + col + " is " + type + ", not numeric");

Object v = rs.getObject(col);
if (!(v instanceof Number || v instanceof Boolean)) {
    throw new IllegalStateException("Expected numeric value, got " + (v == null ? "null" : v.getClass().getName()));
}
Number n = (v instanceof Boolean) ? (((Boolean) v) ? 1 : 0) : (Number) v;

try {
    long v = rs.getLong(col);
} catch (SQLException e) {
    if (e.getMessage() != null && e.getMessage().startsWith("Value is not a number")) {
        Object raw = rs.getObject(col); // handle non-numeric type explicitly
    } else { throw e; }
}

When it happens

Trigger: Calling a numeric getter (getLong, getInt, getDouble, etc.) on a column whose underlying Presto type deserializes to a non-Number Java object, e.g. a VARCHAR, ARRAY, MAP, ROW, or JSON column.

Common situations: Schema drift where a column changed from BIGINT to VARCHAR; developers reading a MAP/ARRAY column with getLong assuming a numeric type; using getString-style assumptions on JSON columns; retrieving the wrong column index and hitting a complex-typed column.

Related errors

• Invalid date from server:
• Expected column to be a timestamp type but is
• No wrapper for
• Result set type must be TYPE_FORWARD_ONLY
• Result set concurrency must be CONCUR_READ_ONLY

AI-assisted analysis of prestodb/presto@55bb57d202 (2026-09-04). Data as JSON: /api/errors/72e589f42be40bc1. Report an issue: GitHub.