1MERGE table1
2USING (SELECT table3.keycolumn,
3 table2.DataColumn1,
4 table2.DataColumn2
5 FROM table2
6 INNER JOIN table3
7 ON table2.anotherKey = table3.anotherKey
8 WHERE table2.anotherKey = 'A1') tmpTable
9ON
10 table1.keyColumn = tmpTable.keyColumn
11WHEN MATCHED THEN
12 UPDATE
13 SET table1.DataColumn1 = tmpTable.DataColumn1
14 ,table1.DataColumn2 = tmpTable.DataColumn2;