Я думал речь про операции внутри запроса.
Вот пример на SQLite набросал:
root@a:~# sqlite3
SQLite version 3.11.0 2016-02-15 17:29:24
Enter ".help" for usage hints.
Connected to a transient in-memory database.
Use ".open FILENAME" to reopen on a persistent database.
sqlite> CREATE TABLE table1(id INT PRIMARY KEY AUTOINCREMENT, fld1 INTEGER , fld2 INTEGER, fld3 INTEGER);
Error: AUTOINCREMENT is only allowed on an INTEGER PRIMARY KEY
sqlite> CREATE TABLE table1(id INTEGER PRIMARY KEY AUTOINCREMENT, fld1 INTEGER , fld2 INTEGER, fld3 INTEGER);
sqlite> CREATE TABLE table2(id INTEGER PRIMARY KEY AUTOINCREMENT, fld1 INTEGER , fld2 INTEGER, fld3 INTEGER);
sqlite> INSERT INTO table1(fld1, fld2, fld3) VALUES(15, 10, 5);
sqlite> INSERT INTO table1(fld1, fld2, fld3) VALUES(3, 6, 9);
sqlite> INSERT INTO table2(fld1, fld2, fld3) VALUES(5, 10, 15);
sqlite> INSERT INTO table2(fld1, fld2, fld3) VALUES(4, 8, 12);
sqlite> SELECT * FROM table1;
1|15|10|5
2|3|6|9
sqlite> SELECT * FROM table2;
1|5|10|15
2|4|8|12
sqlite> SELECT (table1.fld1 * table2.fld1)
...> FROM table1
...> INNER JOIN TABLE2 ON table1.id=table2.id;
75
12
sqlite> SELECT (table1.fld2 * table2.fld2)
...> FROM table1
...> INNER JOIN TABLE2 ON table1.id=table2.id;
100
48
sqlite> SELECT (table1.fld1 * table2.fld1), (table1.fld2 * table2.fld2), (table1.fld3 * table2.fld3)
...> FROM table1
...> INNER JOIN TABLE2 ON table1.id=table2.id;
75|100|75
12|48|108
sqlite>
