Circumstances for the Nested Join Examples
This section provides the partial EXPLAIN outputs for the same two-table join under the following circumstances:
- No nested join
- A nested join where the USI for one table is joined on a column from the other table.
Table Definitions
For these examples, assume the following table definitions:
| Table Name | Column 1 Name | Column 2 Name | Primary Index Name | Unique Secondary Index Name | Number of Rows |
|---|---|---|---|---|---|
| table_1 | NUPI | y_1 | NUPI | none defined | 2 |
| table_2 | NUPI | USI_2 | NUPI | USI_2 | 1,000,000 |
Test Query
The following request is tested against this database, both using and without using nested join:
SELECT * FROM table_1,table_2 WHERE y_1 = USI_2;