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.avg()
Get the aggregate mean of the specified attribute across all matching records.
var average = await Something.avg(numericAttrName, criteria);
Usage
| Argument | Type | Details | |
|---|---|---|---|
| 1 | numericAttrName | The name of the numeric attribute whose mean will be calculated. | |
| 2 | criteria | The Waterline criteria to use for matching records in the database. If no criteria is specified, the average will be computed across all of this model's records. avg queries do not support pagination using skip and limit or projections using select. |
Result
| Type | Description |
|---|---|
| The aggregate mean of the specified attribute across all matching records. |
Errors
| Name | Type | When? |
|---|---|---|
| UsageError | Thrown if something invalid was passed in. | |
| AdapterError | Thrown if something went wrong in the database adapter. | |
| Error | Thrown if anything else unexpected happens. |
See Concepts > Models and ORM > Errors for examples of negotiating errors in Sails and Waterline.
Example
Get the average balance of bank accounts owned by people between the ages of 35 and 45.
var averageBalance = await BankAccount.avg('balance')
.where({
ownerAge: { '>=': 35, '<=': 45 }
});
Notes
- This method can be used with
await, promise chaining, or traditional Node callbacks.- Some databases like MySQL may return
nullfor this kind of query, however it's best practice for Sails/Waterline adapter authors to return0for consistency and type safety in app-level code.
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Reference
- Application
- Blueprint API
- Command-line interface
-
Configuration
- sails.config.*
- sails.config.blueprints
- sails.config.bootstrap()
- sails.config.custom
- sails.config.datastores
- sails.config.globals
- sails.config.http
- sails.config.i18n
- sails.config.log
- sails.config.models
- sails.config.policies
- sails.config.routes
- sails.config.security
- sails.config.session
- sails.config.sockets
- sails.config.views
-
Request (`req`)
- req._startTime
- req.body
- req.cookies
- req.fresh
- req.headers
- req.hostname
- req.ip
- req.ips
- req.isSocket
- req.method
- req.options
- req.originalUrl
- req.params
- req.path
- req.protocol
- req.query
- req.secure
- req.signedCookies
- req.socket
- req.subdomains
- req.url
- req.wantsJSON
- req.xhr
- req.accepts()
- req.acceptsCharsets()
- req.acceptsLanguages()
- req.allParams()
- req.file()
- req.get()
- req.is()
- req.param()
- req.setLocale()
- req.setTimeout()
- req.host
- Response (`res`)
- Waterline (ORM)
- WebSockets
Reference
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