select SQL rows depending on non-identical results of a query - sql

Question

I am trying to select the columns which is relevant without knowing in advance which ones
I do a:
select *
from table
where id = '1'
the result i get is maybe 10 rows and 100+ columns
|id | column1 | column2 | column3 | column4 | column5 |....
| 1 | a | b | c | d | e |....
| 1 | a | XXX | c | d | e |....
| 1 | a | b | c | YYY | e |....
| 1 | a | b | c | d | e |....
For every row, one (or more) of the columns value is different, but i dont know which one(s)
is there any way i can create a temp table with the first query and do a sub query to display only one columns which doesnt have the same value in all the rows?
so the result would look like this:
|id | column2 | column4 |
| 1 | b | d |
| 1 | XXX | d |
| 1 | b | YYY |
| 1 | b | d |
since column 2 and 4 were the ones with non identical data these are the ones I want to see.

Answer 1

As already mentioned, this would require dynamic sql.
Maybe this will help you:
CREATE TABLE Column_Relevance
SELECT id,
COUNT(DISTINCT(column_1))/COUNT(*) AS relevance_column_1,
COUNT(DISTINCT(column_2))/COUNT(*) AS relevance_column_2,
COUNT(DISTINCT(column_3))/COUNT(*) AS relevance_column_3,
# AND SO ON....
GROUP BY id;
All relevance_columns with value < 1 indicate different values for the columns. You can build the whole statement in excel in a few minutes.
Once the table is created, add another column and create a select statement based on the column relevance (e.g. select if(relevance_column_1<1, column_1, else 'ignore') as column_1. This will return the string 'ignore' for all columns, that don't have distinct values.
This is far from perfect but maybe it helps you a little.

Answer 2

Here is a way you could use some aggregation to help. You said you have nearly 100 columns so this could take some effort to create but once it is done it would be fine. And this is just for analysis. You could utilize sys.columns to build the code for you but then we are back in the land of dynamic sql.
declare #Something table
(
ID int
, Column1 varchar(10)
, Column2 varchar(10)
, Column3 varchar(10)
, Column4 varchar(10)
, Column5 varchar(10)
)
insert #Something
values
(1, 'a', 'b', 'c', ' d ', 'e')
, (1, 'a', 'XXX', 'c', ' d ', 'e')
, (1, 'a', 'b', 'c', 'YYY', 'e')
, (1, 'a', 'b', 'c', ' d ', 'e')
;
with MinMax as
(
select ID
, MIN(Column1) as Col1Min
, MAX(Column1) as Col1Max
, MIN(Column2) as Col2Min
, MAX(Column2) as Col2Max
, MIN(Column3) as Col3Min
, MAX(Column3) as Col3Max
, MIN(Column4) as Col4Min
, MAX(Column4) as Col4Max
, MIN(Column5) as Col5Min
, MAX(Column5) as Col5Max
from #Something
group by ID
)
select s.ID
, Column1 = case when mm.Col1Max = mm.Col1Min then '' else s.Column1 end
, Column2 = case when mm.Col2Max = mm.Col2Min then '' else s.Column2 end
, Column3 = case when mm.Col3Max = mm.Col3Min then '' else s.Column3 end
, Column4 = case when mm.Col4Max = mm.Col4Min then '' else s.Column4 end
, Column5 = case when mm.Col5Max = mm.Col5Min then '' else s.Column5 end
from #Something s
join MinMax mm on mm.ID = s.ID

Answer 3

Have you tried using distinct ? It returns only unique rows:
select *
from table
where id = '1'
|id | column2 | column4 |
| 1 | a | a |
| 1 | a | a |
| 1 | b | d |
| 1 | b | d |
select distinct * from table where id= '1'
|id | column2 | column4 |
| 1 | a | a |
| 1 | b | d |
I hope this helps you.