I have a SQL which returns some records. The result may look like this:

PrimaryKey PrimaryKeyChildTable ChildTableField
1                    1                  0
4                    5                  1
8                    6                  2

However, in some particular situations, depending on this big SQL syntax, we might end up with more than one records from the master table such as:

PrimaryKey PrimaryKeyChildTable ChildTableField
1                    1                  0
4                    5                  1
4                    6                  2
5                    8                  1
5                    8                  2
8                    6                  2

So, on top of the SQL syntax I have presently, I would like to add the necessary code so I would filter any record from a duplicate primary key at the child table level and only keep the record from the child table having ChildTableField=1. So, in such circumstances, when I would have two records from the child table in the query result, I would like to obtain this:

PrimaryKey PrimaryKeyChildTable ChildTableField
1                    1                  0
4                    5                  1
5                    8                  1
8                    6                  2