The INFORMATION_SCHEMA.COLUMNS table does not have all data from the <interval_qualifier> of an INTERVAL type descriptor.
In particular, it does not have enough information to implement DatabaseMetaData.getColumns()'s COLUMN_SIZE or DECIMAL_DIGITS columns for INTERVAL types.
1. It does not have the starting and ending units, so we can't distinguish between INTERVAL HOUR TO MINUTE and INTERVAL HOUR TO SECOND--which have different lengths (COLUMN_SIZE) because their string representations have different fields.
2. It does not have the fractional seconds precision.