SQL MINUS/EXCEPT command analog for columns only while INSERTion - sql

Question

Does MINUS/EXCEPT command or code workaround analog exist for columns only? Since MINUS/EXCEPT command fine for rows, how about for columns?
Mask-table (physically exist):
id col1 col2 col3 col4 ... colN comment
doesn't A B C D ... Z --alphabet correct sequence
matter
Columns Data Type of col[i] equals to each other.
Incoming select-stream (not a physical table, but represented as table as a result of other complex joined-selection from other tables):
col1 col2 col3 col4 ... colN comment
A B C D ... Z --alphabet correct seq
A C B D ... Z --incorrect
E B C M ... Z --incorrect
...
Z Y X W ... A --full inverse icorrect
Expected output to physical table after processing mask-table to select-stream as insert result:
id col1 col2 col3 col4 ... colN
(auto-
gnrtd)
(null)(null)(null)(null)...(null)
(null) C B (null)...(null)
E (null)(null) M ...(null)
...
Z Y X W ... A
Please note: alphabet is given just as an example. Not the issue-case here. SQL-Logic/command required. Analog of MINUS/EXCEPT, but for columns (DISTINCT? How, if incoming select-stream is a result of other complex joined-select)
What will be the SQL-code for this task? Please, advise.

Answer 1

Another way to do it without CASE statements:
Setup
CREATE TABLE mask (
col1 TEXT,
col2 TEXT,
col3 TEXT,
col4 TEXT,
col5 TEXT
);
INSERT INTO mask SELECT 'A', 'B', 'C', 'D', 'E';
CREATE TABLE your_stream (
col1 TEXT,
col2 TEXT,
col3 TEXT,
col4 TEXT,
col5 TEXT
);
INSERT INTO your_stream
VALUES
('A', 'B', 'C', 'D', 'E'),
('A', 'C', 'B', 'D', 'E'),
('E', 'B', 'C', 'M', 'E');
Query
SELECT
NULLIF(s.col1, m.col1) AS col1,
NULLIF(s.col2, m.col2) AS col2,
NULLIF(s.col3, m.col3) AS col3,
NULLIF(s.col4, m.col4) AS col4,
NULLIF(s.col5, m.col5) AS col5
FROM your_stream s
CROSS JOIN mask m;
Result
| col1 | col2 | col3 | col4 | col5 |
| ---- | ---- | ---- | ---- | ---- |
| null | null | null | null | null |
| null | C | B | null | null |
| E | null | null | M | null |
View on DB Fiddle

Answer 2

I don't see what the connection to a set operation like EXCEPT would be.
Anyway, this is how you could proceed:
INSERT INTO destination (col1, col2, col3, ...)
SELECT CASE WHEN incoming_col1 <> mask.col1
THEN incoming_col1
END,
CASE WHEN incoming_col2 <> mask.col2
THEN incoming_col2
END,
...
FROM mask;