Question

I have a table like

+ ----------------------- +
| RowID | FromCol | toCol |
+ ----------------------- +
| 1     | a       | b     |
| 2     | b       | c     |
| 3     | c       | d     |
| 4     | c       | b     |
| 5     | b       | a     |
+ ----------------------- +

I would like to remove the rows that has FromCol –> ToCol same value as ToCol –> FromCol
For eg. RowID 1 is a–>b and RowID 5 has b–>a so rowID 5 should be removed. Similarly RowID 4 should be removed because it has a swapped value like RowID 2.

My expected result Table is:

+ ----------------------- +
| RowID | FromCol | toCol |
+ ----------------------- +
| 1     | a       | b     |
| 2     | b       | c     |
| 3     | c       | d     |
+ ----------------------- +

I want to get this as a View preferably with CTE NOT using SQL CURSOR.
Can anybody help me please.
Thanks

Answer 1

Very similar to @Barmar, but using a subquery instead of an inline table.

This works in SQL Server

select t1.*
FROM dbo.MyTest t1
WHERE (SELECT COUNT(t2.rowid) 
         FROM dbo.MyTest t2 
        WHERE t2.toCol= t1.fromCol
          AND t2.fromCol= t1.toCol
          AND t1.rowid> t2.rowid) = 0