JDBC v2: SQLException.getSQLState() returns 22000 (Data Exception) for all server errors, including UNKNOWN_TABLE

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Description

SQLException.getSQLState() returns 22000 ("Data exception") when a query references a table that doesn't exist, instead of a SQLSTATE from the 42xxx class ("Syntax error or access rule violation"), which is the conventional/standard mapping for "table not found" errors.

The root cause is in ExceptionUtils.toSqlState() (jdbc-v2/src/main/java/com/clickhouse/jdbc/internal/ExceptionUtils.java), which maps every ServerException to a hardcoded SQL_STATE_DATA_EXCEPTION = "22000", regardless of the underlying ClickHouse error code:

} else if (cause instanceof ServerException) {
    return new SQLException(exceptionMessage, SQL_STATE_DATA_EXCEPTION, ((ServerException) cause).getCode(), cause);
}

So for UNKNOWN_TABLE (ClickHouse error code 60), the SQLSTATE comes back as 22000 instead of something like 42S02 (the conventional SQLSTATE many databases/drivers use for "table not found"), which is misleading for tooling/ORMs that branch on SQLSTATE class.

Steps to reproduce

1. Connect via the JDBC v2 driver.
2. Execute a query against a table that doesn't exist, e.g. SELECT * FROM not_existing_table.
3. Catch the resulting SQLException and inspect getSQLState().

Error Log or Exception StackTrace

A query executed on unknown table in DBeaver shows this error:

SQL Error [22000]: Code: 60. DB::Exception: <Unreadable error message> (transport error: 404)

Expected Behaviour

getSQLState() should return a SQLSTATE from the 42xxx class (e.g. 42S02) for UNKNOWN_TABLE, not 22000. 22xxx should be reserved for genuine data-value exceptions (e.g. divide-by-zero, invalid datetime, string truncation), per SQL:2003/SQLSTATE conventions.