updating multiple columns using case statement in sql server

Question

I would like to update the table using case statement the query is like this...

select case(@columnname) when 'name1' then 
                                  begin
                                     update table
                                      set 
                                       pay1=pay1* 100
                                       pay2=pay2*20
                                       pay3=pay3* 100
                                  end
                        when 'name2' then 
                                       begin
                                     update table
                                      set 
                                       pay2=pay2*20
                                       pay3=pay3* 100
                                  end

                         when 'name3' then 
                                       begin
                                     update table
                                      set 
                                       pay3=pay3* 100
                                  end
                  end

can u please tell the correct logic to complete the query using case statement

Answer 1

You'll have to swap the syntax around. The case statement will be applied for every value you want to update...

UPDATE table SET
    pay1 = CASE WHEN @columnname IN('name1') THEN pay1 * 100 ELSE pay1 END,
    pay2 = CASE WHEN @columnname IN('name1', 'name2') THEN pay2 * 20 ELSE pay2 END,
    pay3 = CASE WHEN @columnname IN('name1', 'name2', 'name3') THEN pay3 * 100 ELSE pay3 END

It looks like you actually want is a if statement....

IF @columnname = 'name1'
    UPDATE table SET pay1 = pay1 * 100, pay2=pay2*20, pay3=pay3* 100

ELSE IF @ColumnName = 'name2'
    UPDATE table SET pay2 = pay2 * 20, pay3 = pay3 * 100

ELSE IF @ColumnName = 'name3'
    UPDATE table SET pay3 = pay3 * 100

Hope that helps