# FAQ

This page collects some tips that could be useful when creating your first
queries.

## Problem: A metric does not appear in results

Currency related metrics (e.g. metrics.cost_micros) need to include
`segments.date` in the SELECT clause and in the WHERE clause.

## Problem: CONTAINS operator does not work with a string field

When you need to check if a string field contains a substring, don't use the
`CONTAINS` (or `CONTAINS NOT`) operator.

`CONTAINS` is meant to be used with fields that keep lists of values and you
want to check if the list contains one or more specific values.

To check the presence of a substring you can use `REGEXP_MATCH`, for example

    SELECT
      customer.descriptive_name,
      ... // other fields
    FROM
      campaign
    WHERE customer.descriptive_name REGEXEP_MATCH 'Customer.*'

## Learn more

- [Sample queries](https://developers.google.com/search-ads/reporting/query/sample-queries)