Updating multiple columns using Case

Question

I have a query that looks like below:

UPDATE some_table
SET column_x = CASE WHEN x_specific_condition THEN new_value_for_x ELSE column_x END,
    column_y = CASE WHEN y_specific_condition THEN new_value_for_y ELSE column_y END, 
WHERE some_more_conditions

Problem with above is, each column (x, y) still gets updated with their own value if some_more_conditions return true irrespective of their specific conditions returning true. I tried removing ELSE from above, but no luck

I am combining as some_more_conditions are same for both cases, I think its better to perform all in 1 update (suggestions welcome)

Do you know if there is a way that I can perform the above update in 1 query by skipping the individual columns where the specific conditions do not match (basically avoid overwriting of same values)

Answer 1

To do this in one update, you would need to expand the where clause:

UPDATE some_table
    SET column_x = CASE WHEN x_specific_condition THEN new_value_for_x ELSE column_x END,
        column_y = CASE WHEN y_specific_condition THEN new_value_for_y ELSE column_y END, 
    WHERE some_more_conditions AND
          (x_specific_condition OR
           y_specific_condition
          );

An alternative is to use multiple updates, but that could be more expensive:

UPDATE some_table
    SET column_x = new_value_for_x
    WHERE some_more_conditions AND x_specific_condition;

UPDATE some_table
    SET column_y = new_value_for_y
    WHERE some_more_conditions AND y_specific_condition;

Answer 2

update [table_name] set [column_name_1] = case when [column_name_1] = [condition_1] then [condition_2] else [column_name_1] end, [column_name_2] = case when [column_name_2] = [condition_1] then [condition_2] else [column_name_2] end, where condition;

Note: [table_name] is your table name, [column_name] is your column name in which you want to update values. you can update values without where condition as well.

find screenshot