How to Search on Two Keys?

[robocop]

Searchong different keys combines with -

SELECT field1_index, field2_index FROM test_table
WHERE field1_index = '1' OR field2_index = '1'

Each SELECT searches only one key and can be optimized:

SELECT field1_index, field2_index
FROM test_table WHERE field1_index = '1'
UNION
SELECT field1_index, field2_index
FROM test_table WHERE field2_index = '1';