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Last tested: Nov 16, 2017
The history explore in System Activity includes both User-Defined and LookML dashboards. Because of this, when filtering on a dashboard id, the generated SQL will convert the ID to a VARCHAR.
If you try to filter on a dashboard id within a custom filter, you might get the error message data exception: invalid character value for cast (if they are on a HyperSQL back-end). To get around this, change your custom filter to be:
concat(${history.dashboard_id},"") = "58"
This will cast the dashboard ID to a VARCHAR in the generated SQL and filter correctly.
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