Cycle through columns and change value is empty-CodePudding

I have the following table that is comparing two similar tables:

Source	Part	Info 1	Info 2	...	Info 12	Description	Color
Table 1	Wheel	Circle		...	Long Distance
Table 2	Wheel	Circle	Rubber	...	Long Distance	Wheel for vehicle	Black
Table 1	Seat		4 Seats	...	Comfortable		Brown
Table 2	Seat	Leather	4 Seats	...	Comfortable	Seat for vehicle	Brown

I am trying to update the columns in Table 1 where it doesn't have the value of table 2.

I currently have the update query that works on a single field at one time but I am wondering if there is a way to make it dynamic and run through all the columns on a single run. Here is my working query right now:

UPDATE t
SET INFO2 = f.INFO2
FROM Table1 t
JOIN Table2 f ON f.PART = t.PART
WHERE t.INFO2 = '';

CodePudding user response：

Using a CASE expression to update NULL / empty string column, leave it as it is otherwise

UPDATE t
  SET INFO2 = case when coalesce(t.INFO2, '') = '' then f.INFO2 else t.INFO2 end, 
      INFO3 = case when coalesce(t.INFO3, '') = '' then f.INFO3 else t.INFO3 end, ..
FROM Table1 t
JOIN Table2 f ON f.PART = t.PART ;