As of Looker 3.38, the decimals parameter as well as the int field type are being deprecated and moved to the Admin > Legacy Features panel.
The reason for these deprecations is to simplify how Looker handles number values by providing a single field type (number) and a single, flexible way to format them through Excel-style format definitions.
Deprecations
1. Deprecated decimals parameter
Starting in 3.38, the decimals parameter is deprecated. It will continue to work so long as the LookML “decimals” Parameter and “int” Field Type legacy feature is turned on, but each occurrence in a model will produce a deprecation warning in the LookML Validator.
The new way to format numbers is with either the value_format or value_format_name parameter (see below).
2. Deprecated value truncation when decimals is not specified
Prior to 3.38, a number field that did not specify decimals would truncate the number value to zero decimal places. (i.e 0.535 would become 0).
This could result in misleading queries and developer confusion. To remedy this, number fields will now show the entire number as returned by the databse by default. To format the number differently, use value_format or value_format_name.
This change in behavior is also controlled by the LookML “decimals” Parameter and “int” Field Type. Disabling this legacy feature allows this new, clearer default behavior.
3. Deprecated int field type
Starting in 3.38, specifying type: int on a dimension or measure is deprecated. It will continue to work so long as the LookML “decimals” Parameter and “int” Field Type legacy feature is turned on, but each occurrence in a model will produce a deprecation warning in the LookML Validator.
type: number should be used instead.
The purpose of the int field type was to show number values with no formatting (thousands separators) or decimals, as is often desired for ID fields. Since deprecating type: int in favor of type: number, Looker is now smart about whether or not to show thousands separators and decimals by default based on the name of the field. If the field name is id, ends with _id, or if primary_key: true is set on the field, no thousands separators or decimals will be shown.
If a field should not have thousands separators or decimals but does not follow one of the above patterns, the equivalent of type: int can be achieved by using type: number with the id value format:
- dimension: my_cool_dimension
type: number
value_format_name: id
...
See below for more information on the value_format and value_format_name parameters.
Formatting Numbers
The proper way to format numbers is with value formats. A value format can be defined on the fly for a field with the value_format parameter, or a named value format can be defined and referenced by multiple fields via the value_format_name parameter.
1. value_format parameter
The syntax for defining a value format in LookML is the same as for Excel. Example:
- dimension: order_profit
type: number
value_format: "#,##0.0"
sql: ${TABLE}.order_profit
This will cause all order_profit values to be displayed with thousands separators (commas) and one decimal place.
2. Custom value_formats and the value_format_name parameter
If a format is used for multiple fields, it can be helpful to define it once and simply refer to it by name whenever it is needed. This is done in a model file as follows:
- value_formats:
- name: telephone
value_format: "(###) ###-####"
Then to use this named value format for a field:
- dimension: phone_number_formatted
type: number
value_format_name: telephone
sql: ${TABLE}.phone_number
Looker also provides the following set of built-in formats:
| Name | Description | Format String | Example |
|---|---|---|---|
| id | number with no commas | 0 | 1234 |
| decimal_0 | 0 decimals | #,##0 | 1,234 |
| decimal_1 | 1 decimal | #,##0.0 | 1,234.5 |
| decimal_2 | 2 decimals | #,##0.00 | 1,234.56 |
| decimal_3 | 3 decimals | #,##0.000 | 1,234.567 |
| decimal_4 | 4 decimals | #,##0.0000 | 1,234.5678 |
| usd_0 | U.S. dollars | $#,##0 | $1,234 |
| usd | U.S. dollars w/ cents | $#,##0.00 | $1,234.56 |
| percent_0 | percent w/ 0 decimals | #,##0"%" | 12% |
| percent_1 | percent w/ 1 decimal | #,##0.0"%" | 12.3% |
| percent_2 | percent w/ 2 decimals | #,##0.00"%" | 12.34% |
| percent_3 | percent w/ 3 decimals | #,##0.000"%" | 12.345% |
| percent_4 | percent w/ 4 decimals | #,##0.0000"%" | 12.3456% |
