Hello, I have to join between data sources tables E and A. Table E has 4 columns ( E_A , E_B , E_C , E_D ) which I need to join to ( T_A , T_B , T_C , T_D ) from Table T and get the ( T_ID ) My columns of Table E can have 1, 2 or 3 null values. For example I can have E_C = null but the Other are completed. I thought that with an “outer left join” I can get the wright T_ID even if I have one field with null value. However, it gets the wright T_ID when all fields are not null and 0 when one or more of the columns are missing. How can I join lines even if I have 1, 2, 3 or 4 not null fields and recover the right to T_ID all the time?
I'm not sure I entirely understand this situation fully, but a workaround to joining nulls would be to find a value that is unique and replace all nulls with that value before you do the join. In Oracle you might use the NVL function to do this. In Talend you simply want to replace where the value is null.
For example, in Talend you could use something like this to prepare your data.....
