Did you know that PS Query expressions can be used to perform many of the SQL functions you may need? Multiple values of a field (ex. Student groups) can be displayed within one field using listagg. Without needing subqueries, multiple field values can be displayed on one row, using Nth Value. Aggregate function, such as SUM, SUMIFS, AVERAGE, AVERAGEIFS, and simple mathematical functions (addition, subtraction, multiplication, division) can all be performed within PS Query expressions. Check out these Alliance presentations (and many more in the HEUG file library) for more:
Express Yourself! Using Conditional Expressions in SQL or PSQuery
Aggregate reporting in multiple dimensions using PS Query
Making PS Query aggregate and flatten your data like a champ