Custom value in header depending on value in lines

[salto]

Hello,

I am reading a Quality Control table, it has a header with the QualityControl ID and several lines in other table:

QualityControlHeader:

LOAD

    "No_" as ControlID

SQL SELECT *

FROM QualityControlHeader;

left join LOAD

    LineOnTest,        //TRUE or FALSE        

    NumControl as ControlID;

SQL SELECT *

FROM QualityControlLines;

I would like to add a field in the table (which is not in the data source): if all the lines for a ControlID are TRUE for the LineOnTest field, a new field in the Header (HeaderOnTest) has to be TRUE. If not, the value for this field needs to be FALSE.

How can this be carried out? Thanks.