SQLite UPDATE now working or I have done wrong - sqlite

Question

Current table questions:
rowid: 1 | 2 | 3 | 4 | 5
id: 3 | 4 | 7 | 9 | 10
Trying to achieve the following:
rowid: 1 | 2 | 3 | 4 | 5
id: 1 | 2 | 3 | 4 | 5
I have tried many different variations of SQL without success, this is the latest I am testing:
UPDATE questions SET id = rowid;
Can someone please suggest how I solve this as I have googled and cannot find the solution?

Answer 1

I don't believe that your question completely encompasses all aspects of the issue.
In theory to have a table (the before table) where SELECT rowid, id results in
rowid: 1 | 2 | 3 | 4 | 5
id: 3 | 4 | 7 | 9 | 10
The id column must not be an alias of the rowid column (otherwise the values would be identical)
However, if the id column is an alias of the rowid column, the both columns would be the same so the before table above would not be as above.
As an example using :-
--<<<<<<<<<< WORKS >>>>>>>>>>
-- as ID is not an alias of the rowid column update changes id column
DROP TABLE IF EXISTS questionsv3;
CREATE TABLE IF NOT EXISTS questionsv3 (ID INTEGER);
INSERT INTO questionsv3 VALUES (3),(4),(7),(9),(10);
SELECT rowid, id FROM questionsv3;
UPDATE questionsv3 SET id = rowid;
SELECT rowid, id FROM questionsv3;
results in the expected result as per :-
First Select (before update) :-
Second Select (after update)
Other potential causes
rowid is not in fact the rowid as per SQLITE, but a conceptual idea that it should be 1,2,3 ...... (in which case using VACUUM, if there is no alias to the rowid, may result in the desired re-numbering of the rowid column, which if followed by the update may then result in the id being re-sequenced).
That the update is done within a transaction that hasn't been committed and is rolled back.
You may wish to consider the following permutations of different table creations (see comments) :-
-- as ID is an alias of rowid, then rowid is set according to ID so update does nothing
DROP TABLE IF EXISTS questionsv1;
CREATE TABLE IF NOT EXISTS questionsv1 (ID INTEGER PRIMARY KEY);
INSERT INTO questionsv1 VALUES (3),(4),(7),(9),(10);
SELECT rowid, id FROM questionsv1;
UPDATE questionsv1 SET id = rowid;
SELECT rowid, id FROM questionsv1;
-- as ID is an alias of the rowid column, then rowid is set according to the ID so update does nothing
DROP TABLE IF EXISTS questionsv2;
CREATE TABLE IF NOT EXISTS questionsv2 (ID INTEGER PRIMARY KEY AUTOINCREMENT);
INSERT INTO questionsv2 VALUES (3),(4),(7),(9),(10);
SELECT rowid, id FROM questionsv2;
UPDATE questionsv2 SET id = rowid;
SELECT rowid, id FROM questionsv2;
--<<<<<<<<<< WORKS >>>>>>>>>>
-- as ID is not an alias of the rowid column update changes id column
DROP TABLE IF EXISTS questionsv3;
CREATE TABLE IF NOT EXISTS questionsv3 (ID INTEGER);
INSERT INTO questionsv3 VALUES (3),(4),(7),(9),(10);
SELECT rowid, id FROM questionsv3;
UPDATE questionsv3 SET id = rowid;
SELECT rowid, id FROM questionsv3;
--<<<<<<<<<< WORKS >>>>>>>>>>
-- as ID is not an alias of rowid the ID column is updated accordingly
DROP TABLE IF EXISTS questionsv4;
CREATE TABLE IF NOT EXISTS questionsv4 (ID TEXT PRIMARY KEY); -- not an alias of rowid
INSERT INTO questionsv4 VALUES (3),(4),(7),(9),(10);
SELECT rowid, id FROM questionsv4;
UPDATE questionsv4 SET id = rowid;
SELECT rowid, id FROM questionsv4;
--<<<<<<<<<< FAILS >>>>>>>>>>
DROP TABLE IF EXISTS questionsv13;
CREATE TABLE IF NOT EXISTS questionsv13 (ID INTEGER PRIMARY KEY) WITHOUT ROWID;
INSERT INTO questionsv13 VALUES (3),(4),(7),(9),(10);
SELECT id FROM questionsv13;
UPDATE questionsv13 SET id = rowid; -- would fail no such column
SELECT id FROM questionsv13;