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

Solution

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