Table 1:
Algorithms used in implementing QDM logical operators
| Operator | Algorithm Steps |
|---|---|
| AND | |
| 1. Inner join two input tables using appropriate columns; 2. Filter columns for the output table; 3. Remove duplicated rows (with GroupBy). |
|
| AND NOT | |
| 1. Add a column with non-null values to right-hand-side input table; 2. Left outer join two input tables using appropriate columns; 3. Filter and keep rows that have null in the added column from step 1; 4. Filter columns for the output table and remove duplicated rows. |
|
| OR | |
| 1. Filter appropriate columns from both input tables; 2. Concatenate the two trimmed input tables and remove duplicated rows. |
|