ResultSetMetaData.getSchemaName() returns empty string for aliased columns #3186
Description
I'm sometimes using the ResultSetMetaData to query the INFORMATION_SCHEMA.COLUMNS table based on table catalog, table schema, table name and column name.
However, when AS is used to change the label in the result set, the schema name becomes the empty string and thus the lookup from COLUMNS fails.
Example:
CREATE TABLE test(col1 int, col2 varchar);
INSERT INTO test VALUES(10, 't1');
SELECT col1, col2 AS second FROM test;Here is the ResultSetMetaData according to DBeaver:
| Name | Label | # | Type | Catalog Name | Schema Name | Table Name | Max Length | Precision | Scale | JDBC Type | Not Null | Auto |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| COL1 | COL1 | 0 | INTEGER | _DIVINE_URI_TEST_ | PUBLIC | TEST | 11 | 10 | 0 | INTEGER | false | false |
| COL2 | SECOND | 1 | VARCHAR | _DIVINE_URI_TEST_ | TEST | 2147483647 | 2147483647 | 0 | VARCHAR | false | false |