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Use parameters with metric views

Parameters let you pass values into a metric view when you query it. Use parameters to reuse a single metric view definition across different inputs, such as a discount rate or a date window. Reference a parameter anywhere a constant SQL expression is valid, such as in filters, field and measure expressions, the source, and joins. Pass a value as an argument when you query the view.

Parameters reduce duplication. Instead of maintaining a separate metric view for each variant, you define the logic once and let each caller supply its own values. A parameter can include a default value, so callers that don't pass an argument fall back to the default.

note

Materialization isn't currently supported for metric views that define parameters.

Requirements​

Querying a metric view that defines parameters requires a compute resource that meets the minimum version requirements. See Metric view feature availability for minimum compute version requirements.

Define parameters​

You can define parameters in the Catalog Explorer low-code editor or directly in YAML. After you create a parameter, reference it by name anywhere a constant SQL expression is valid, such as in filters, field and measure expressions, the source, and joins.

To add a parameter in the low-code editor:

  1. In the editor heading, click Add parameter.
  2. Enter a parameter name, for example start_date or offset_int.
  3. Enter a default value and data type.
  4. Click Save.

The parameter appears in the editor heading after you create it.

To define parameters in YAML, add a top-level parameters block to the metric view definition. For the complete field reference and a YAML example, see Parameters.

Query a metric view with parameters​

To query a metric view that defines parameters, call the metric view as a table-valued function and pass parameters as arguments. You can pass arguments by name or by position, or omit them to use the default values.

Pass arguments by name​

To pass an argument by name, use the => operator. The following example passes a discount value of 0.15:

SQL
SELECT product, MEASURE(discountedSales)
FROM catalog.schema.metric_view(discount => 0.15)
GROUP BY product;

Pass arguments by position​

To pass arguments by position, list the values in the order the parameters are defined. The following example passes the same discount value of 0.15:

SQL
SELECT product, MEASURE(discountedSales)
FROM catalog.schema.metric_view(0.15)
GROUP BY product;

Use default parameter values​

To use the default parameter values when you call the metric view, omit arguments. The following queries are equivalent and use all default values:

SQL
SELECT product, MEASURE(discountedSales) FROM catalog.schema.metric_view() GROUP BY product;
SELECT product, MEASURE(discountedSales) FROM catalog.schema.metric_view GROUP BY product;

View the parameters a metric view defines​

To see the parameters that a metric view defines, view its YAML definition, which includes the parameters block. See View metric view definition and metadata.

Additional resources​

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