Fixed bug with CSV export

[sarjona]

Our databases are Oracle and we've detected this bug in some cases (with MySQL is working properly). We've tried to find a generic solution (in Oracle, converting TO_CHAR the qrX.response field is also working).

Tested in Moodle 3.1.1 with MySQL and Oracle databases.

[danmarsden]

tried this patch but we still get a failure with the date fields when using postgres.

hardcoding this seems to fix it for us: (postgresql specific code though)
if ($field === 'response') {
$extraselect .= "CAST($alias AS TEXT) AS $field";
} else {

here's the error in Postgres

Debug info: ERROR: UNION types text and date cannot be matched
LINE 24: 0 AS choice_id, qrd.response AS response,...
^

SELECT qr.id || '' || 'dropdown' || '' || qrs.id AS id,
qr.submitted, qr.complete, qr.grade, qr.username, u.firstnamephonetic, u.lastnamephonetic, u.middlename, u.alternatename, u.firstname, u.lastname, u.username, u.department, u.institution, u.id as userid, qr.id AS rid, qrs.question_id,
qrs.choice_id, qro.response, 0 AS rank
FROM mdl_questionnaire_response qr
JOIN mdl_questionnaire_resp_single qrs ON qrs.response_id = qr.id

AND qr.survey_id = $1 AND qr.complete = $2
LEFT JOIN mdl_questionnaire_response_other qro ON qro.response_id = qr.id AND qro.choice_id = qrs.choice_id
LEFT JOIN mdl_user u ON u.id = CAST(qr.username AS INT)
WHERE qr.id = $3 UNION ALL
SELECT qr.id || '' || 'textbox' || '' || qrt.id AS id,
qr.submitted, qr.complete, qr.grade, qr.username, u.firstnamephonetic, u.lastnamephonetic, u.middlename, u.alternatename, u.firstname, u.lastname, u.username, u.department, u.institution, u.id as userid, qr.id AS rid, qrt.question_id,
0 AS choice_id, qrt.response AS response, 0 AS rank
FROM mdl_questionnaire_response qr
JOIN mdl_questionnaire_response_text qrt
ON qrt.response_id = qr.id

AND qr.survey_id = $4 AND qr.complete = $5
LEFT JOIN mdl_user u ON u.id = CAST(qr.username AS INT)
WHERE qr.id = $6 UNION ALL
SELECT qr.id || '' || 'date' || '' || qrd.id AS id,
qr.submitted, qr.complete, qr.grade, qr.username, u.firstnamephonetic, u.lastnamephonetic, u.middlename, u.alternatename, u.firstname, u.lastname, u.username, u.department, u.institution, u.id as userid, qr.id AS rid, qrd.question_id,
0 AS choice_id, qrd.response AS response, 0 AS rank
FROM mdl_questionnaire_response qr
JOIN mdl_questionnaire_response_date qrd
ON qrd.response_id = qr.id

AND qr.survey_id = $7 AND qr.complete = $8
LEFT JOIN mdl_user u ON u.id = CAST(qr.username AS INT)
WHERE qr.id = $9 UNION ALL
SELECT qr.id || '' || 'yesno' || '' || qrb.id AS id,
qr.submitted, qr.complete, qr.grade, qr.username, u.firstnamephonetic, u.lastnamephonetic, u.middlename, u.alternatename, u.firstname, u.lastname, u.username, u.department, u.institution, u.id as userid, qr.id AS rid, qrb.question_id,
0 AS choice_id, qrb.choice_id AS response, 0 AS rank
FROM mdl_questionnaire_response qr
JOIN mdl_questionnaire_response_bool qrb ON qrb.response_id = qr.id

AND qr.survey_id = $10 AND qr.complete = $11
LEFT JOIN mdl_user u ON u.id = CAST(qr.username AS INT)
WHERE qr.id = $12 ORDER BY userid, id
[array (
0 => '904',

[mchurchward]

Thanks. I'll look at this later this week.

[mchurchward]

Can one of you explain what the actual issue is? Is there a specific response type that is failing? What is the actual data types of expected type vs. that actual type causing the issue?

[sarjona]

In Oracle the problem is because of the CLOB fields (TEXT in Moodle), which have a lot of problems comparing directly and need converting them to varchar or similar.
I'm not sure if this answer all your questions but if I can help you, tell us :-)

[mchurchward]

Hi.
I still don't get what lines like these are intended to do:
"$DB->sql_compare_text($alias . '.' . $field, 1000)."

My understanding of the "sql_compare_text" function is that it is used to return sql that allows comparison of a text field to a varchar field. But, you aren't using it in a compare context. You are using it where the variable is listed in the "SELECT" part. Does that make sense to to? Also, why "1000"?

[sarjona]

Replaced sql_compare_text to sql_order_by_text function and opened new PR: #73