The complete execution sequence of the SQL Select statement:
1. The from clause assembles data from different data sources ;
2. The where clause filters the record rows based on the specified conditions;
3. The group by clause divides the data into multiple groups;
4. Use aggregate functions for calculation;
5. Use the having clause to filter groups;
6. Calculate all expressions;
7. Select set output;
8. Use order by to sort the result set.
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