Add missing reserved keywords to Sqlglot Exasol dialect

[nnamdi16]

Description

Exasol reserved keywords defined in the official Exasol keyword list are currently not included in SQLGlot’s Exasol dialect.

These keywords are defined in the Exasol system table:

SELECT keyword
FROM EXA_SQL_KEYWORDS
WHERE RESERVED = TRUE;

Missing reserved keywords can lead to incorrect parsing behaviour, especially when identifiers conflict with reserved words.

For example, SQLGlot may incorrectly allow reserved keywords as identifiers:

SELECT * FROM my_table as cs;

This should fail or require quoting in Exasol.

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Proposed solution

Add the missing reserved keywords to the Exasol dialect tokenizer KEYWORDS set.

[nnamdi16]

The issue has been resolved: tobymao#7086