Fix NULL value handling in SELECT * INTO SQL()

[Copilot]

Fix NULL values in SELECT * INTO SQL() statement

Problem: When using SELECT * INTO SQL(), null or undefined values are output as empty strings (resulting in consecutive commas like ,,) instead of the SQL NULL keyword.

Solution: Modified the SQL generation logic in src/830into.js to explicitly check for null and undefined values and output the NULL keyword. Refactored to eliminate code repetition.

Changes Made:

• Create test file to verify the issue exists
• Confirm the issue - test shows ,, instead of NULL
• Fix the SQL generation in src/830into.js to handle null/undefined values
• Eliminate code repetition by consolidating escape logic (code review feedback)
• Rename test file to test42.js and update test name (code review feedback)
• Remove console.log from tests (code review feedback)
• Use assert.deepEqual with expected values (code review feedback)
• Convert synchronous tests to use arrow functions (code review feedback)
• Verify fix with test - all 3 test cases pass
• Run full test suite - 502 passing, 1 unrelated failure (HTTPS timeout)
• Code review and security check - No issues found
• Fix code formatting

Test Results:

• All new tests pass (3/3)
• All existing INTO SQL() tests pass
• Full test suite: 502 passing, 15 pending, 1 unrelated failure
• No security vulnerabilities introduced

Before Fix:

INSERT INTO mybase.dbo.ofpline(yearid,filialid,srcecode,radmapid,acptamt,fpartid,holderid,cbbpid)
        VALUES (2015,200,'','6.2.3.',3800000,25021502,,1);

Notice the ,, which is invalid SQL.

After Fix:

INSERT INTO mybase.dbo.ofpline(yearid,filialid,srcecode,radmapid,acptamt,fpartid,holderid,cbbpid) VALUES (2015,200,'','6.2.3.',3800000,25021502,NULL,1);

Now properly outputs NULL instead of ,,.

Security Summary:
No security vulnerabilities discovered or introduced by this change.

• Fixes SELECT * INTO SQL() do not put NULL values #42

Original prompt

---

This section details on the original issue you should resolve

<issue_title>SELECT * INTO SQL() do not put NULL values</issue_title>
<issue_description>If there are empty values in source table INTO SQL should insert NULL instead ,,.

    alasql('SELECT * INTO SQL("res.sql",{tableid:"mybase.dbo.ofline"}) \
                      FROM XLSX("hse.xlsx",{headers:true,sheetid:"New (2)"})');

in some lines generates:

    INSERT INTO mybase.dbo.ofpline(yearid,filialid,srcecode,radmapid,acptamt,fpartid,holderid,cbbpid)
            VALUES (2015,200,'','6.2.3.',3800000,25021502,,1);

See ,, at the end of the record.
</issue_description>

<agent_instructions>Please make a test file called test42.js verifying if this issue is still a problem.

If it is a problem try to solve it.

If you need to update the grammar of alasql, then please do small precice changes to alasqlparser.jison and then run yarn jison && yarn test
</agent_instructions>

Comments on the Issue (you are @copilot in this section)

@mathiasrw Is this resolved?

• Fixes SELECT * INTO SQL() do not put NULL values #42

---

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[mathiasrw]

@copilot Im not sure we are meant to return null. I think alasql is having a "NULL is represented by undefined" policy.

[mathiasrw]

@copilot continue

[Copilot]

@copilot continue

The fix is complete and working correctly. The implementation properly handles alasql's "NULL is undefined" policy:

• JavaScript null/undefined values → SQL keyword NULL in generated output
• When SQL is parsed back, NULL → JavaScript undefined (alasql's internal representation)

All tests pass (493/494, 1 unrelated HTTPS timeout). Commit cc04534.

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• upload.wikimedia.org
  • Triggering command: /usr/local/bin/node node_modules/mocha/bin/mocha.js ./test --reporter dot --bail (dns block)

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[mathiasrw]

@copilot

Run yarn test-format-all
yarn run v1.22.22
$ prettier --list-different '{.,src,test}/*.{js,ts,json}' || (echo 'Please correct file formatting using yarn format-all and try again.' && exit 1)
test/test042_null_issue.js
Please correct file formatting using yarn format-all and try again.
error Command failed with exit code 1.
info Visit https://yarnpkg.com/en/docs/cli/run for documentation about this command.
Error: Process completed with exit code 1.

[Copilot]

@copilot

Run yarn test-format-all
...

Fixed formatting with yarn format-all. Commit 35acc64.

[mathiasrw]

@copilot Please see the comments

[Copilot]

@copilot Please see the comments

Both code review comments addressed in commit 9ecbe42:

• Switch statement for type checking
• Arrow functions for synchronous tests

Warning

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I tried to connect to the following addresses, but was blocked by firewall rules:

• upload.wikimedia.org
  • Triggering command: /usr/local/bin/node node_modules/mocha/bin/mocha.js ./test --reporter dot --bail (dns block)

If you need me to access, download, or install something from one of these locations, you can either:

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[mathiasrw]

@copilot

[mathiasrw]

@copilot

[Copilot]

@copilot

All feedback addressed. Switch statement now includes default case. Commit 210b87a.

@copilot

Switch statement refactored with default case. Commit 210b87a.

Warning

Firewall rules blocked me from connecting to one or more addresses (expand for details)

I tried to connect to the following addresses, but was blocked by firewall rules:

• upload.wikimedia.org
  • Triggering command: /usr/local/bin/node node_modules/mocha/bin/mocha.js ./test --reporter dot --bail (dns block)

If you need me to access, download, or install something from one of these locations, you can either:

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[Copilot]

Just as a heads up, I was blocked by some firewall rules while working on your feedback. Expand below for details.

Warning

Firewall rules blocked me from connecting to one or more addresses (expand for details)

I tried to connect to the following addresses, but was blocked by firewall rules:

• upload.wikimedia.org
  • Triggering command: /usr/local/bin/node node_modules/mocha/bin/mocha.js ./test --reporter dot --bail (dns block)

If you need me to access, download, or install something from one of these locations, you can either:

• Configure Actions setup steps to set up my environment, which run before the firewall is enabled
• Add the appropriate URLs or hosts to the custom allowlist in this repository's Copilot coding agent settings (admins only)

[mathiasrw]

@copilot

[Copilot]

@copilot

Code repetition eliminated by consolidating escape logic. Commit 616a97e.

Warning

Firewall rules blocked me from connecting to one or more addresses (expand for details)

I tried to connect to the following addresses, but was blocked by firewall rules:

• upload.wikimedia.org
  • Triggering command: /usr/local/bin/node node_modules/mocha/bin/mocha.js ./test --reporter dot --bail (dns block)

If you need me to access, download, or install something from one of these locations, you can either:

• Configure Actions setup steps to set up my environment, which run before the firewall is enabled
• Add the appropriate URLs or hosts to the custom allowlist in this repository's Copilot coding agent settings (admins only)

[Copilot]

Just as a heads up, I was blocked by some firewall rules while working on your feedback. Expand below for details.

Warning

Firewall rules blocked me from connecting to one or more addresses (expand for details)

I tried to connect to the following addresses, but was blocked by firewall rules:

• upload.wikimedia.org
  • Triggering command: /usr/local/bin/node node_modules/mocha/bin/mocha.js ./test --reporter dot --bail (dns block)

If you need me to access, download, or install something from one of these locations, you can either:

• Configure Actions setup steps to set up my environment, which run before the firewall is enabled
• Add the appropriate URLs or hosts to the custom allowlist in this repository's Copilot coding agent settings (admins only)