Retrieving Google AdWords data
Google AdWords data is organized into various metrics (for example, Conversions, Impressions, and InvalidClicks), which can be grouped by various segments (for example, Date and Device). Additionally, there are attributes that represent fixed data or account settings (for example, CampaignName, AdType, and AdGroupStatus). These are called the Behavior for the field. There are many valid combinations of metrics, segments, and attributes. The driver surfaces each separate report type in AdWords as a table.
Unlike most database tables, it is not very helpful to select all metrics, segments, and attributes in a given table. In some cases, it is not even possible to do this since some data conflict with each other when selected. As a result, the driver thus interprets the SELECT * query to mean a default set of metrics, segments, and attributes are requested. This includes queries that explicitly select all columns to account for tools that use projection when returning results. These default fields represent the default columns exposed through the Google AdWords console. To select nondefault columns, simply explicitly select these columns in the query rather than issuing a SELECT * query. Finally, it is important to note that at least one metric must be included in the request for any data to be returned.
By default, the column names are the values used by the API.
Certain percentage fields can return the values '< 10%' or '> 90 %'. In order to allow you to use this column as a numeric field, these values are reported as exactly '10' and '90' respectively.