Metrics SQL Syntax and Capabilities
Metrics SQL is a specialized SQL dialect designed exclusively for querying data from metrics views.
Querying Fundamentals
Metrics SQL transforms queries that reference dimensions
and measures
within a metrics view
into their corresponding database columns or expressions. This transformation is based on the mappings defined in a metrics view YAML configuration, enabling reuse of dimension or measure definitions. Additionally any security policies defined in metrics_view is also inherited.
Example: Crafting a Metrics SQL Query
Consider a metrics view configured as follows:
type: metrics_view
title: Ad Bids
model: ad_bids
timeseries: timestamp
dimensions:
- label: Publisher
name: publisher
column: toUpper(publisher)
description: ""
- label: Domain
name: domain
column: domain
description: ""
measures:
- name: total_records
label: Total records
expression: COUNT(*)
description: ""
format_preset: humanize
valid_percent_of_total: true
To query this view, a user might write a Metrics SQL query like:
SELECT publisher, domain, total_records FROM metrics_view
This Metrics SQL is internally translated to a standard SQL query as follows:
SELECT toUpper(publisher) AS publisher, domain AS domain, COUNT(*) AS total_records FROM ad_bids GROUP BY publisher, domain
Supported SQL Features
- SELECT statements with plain
dimension
andmeasure
references. - A single FROM clause referencing a
metrics view
. - WHERE clause that can reference selected
dimensions
only. - Operators in WHERE and HAVING clauses include
=
,!=
,>
,>=
,<
,<=
, IN, LIKE, AND, OR, and parentheses for structuring the expression. - HAVING clause for filtering on aggregated results, referencing selected dimension and measure names. Supports the same expression capabilities as the WHERE clause.
- ORDER BY clause for sorting the results.
- LIMIT and OFFSET clauses for controlling the result set size and pagination.
Caution : The Metrics SQL feature is currently evolving. We are dedicated to enhancing the syntax by introducing additional SQL features, while striving to maintain support for existing syntax. However, please be advised that backward compatibility cannot be guaranteed at all times. Additionally, users should be aware that there may be untested edge cases in the current implementation. We appreciate your understanding as we work to refine and improve this feature.
Security and Compliance
Queries executed via Metrics SQL are subject to the security policies and access controls defined in the metrics view YAML configuration, ensuring data security and compliance.
Limitations
Metrics SQL is specifically designed for querying metrics views and may not support all features found in standard SQL. Its primary focus is on providing an efficient and easy way to extract data within the constraints of metrics view configurations.