An ActiveQuery can be a normal query or be used in a relational context.
ActiveQuery instances are usually created by [[ActiveRecord::find()]].
Relational queries are created by [[ActiveRecord::hasOne()]] and [[ActiveRecord::hasMany()]].
Normal Query
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ActiveQuery mainly provides the following methods to retrieve the query results:
- ActiveQuery::one: returns a single record populated with the first row of data.
- ActiveQuery::all: returns all records based on the query results.
- ActiveQuery::count: returns the number of records.
- ActiveQuery::sum: returns the sum over the specified column.
- ActiveQuery::average: returns the average over the specified column.
- ActiveQuery::min: returns the min over the specified column.
- ActiveQuery::max: returns the max over the specified column.
- ActiveQuery::scalar: returns the value of the first column in the first row of the query result.
- ActiveQuery::exists: returns a value indicating whether the query result has data or not.
You can use query methods, such as [[where()]], [[limit()]] and [[orderBy()]] to customize the query options.
ActiveQuery also provides the following additional query options:
- [[with()]]: list of relations that this query should be performed with.
- [[indexBy()]]: the name of the column by which the query result should be indexed.
- [[asArray()]]: whether to return each record as an array.
These options can be configured using methods of the same name. For example:
php
$customers = Customer::find()->with('orders')->asArray()->all();
Relational query
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In relational context ActiveQuery represents a relation between two Active Record classes.
Relational ActiveQuery instances are usually created by calling [[ActiveRecord::hasOne()]] and
[[ActiveRecord::hasMany()]]. An Active Record class declares a relation by defining
a getter method which calls one of the above methods and returns the created ActiveQuery object.
A relation is specified by [[link]] which represents the association between columns
of different tables; and the multiplicity of the relation is indicated by [[multiple]].
If a relation involves a junction table, it may be specified by [[via()]].
This methods may only be called in a relational context. Same is true for [[inverseOf()]], which
marks a relation as inverse of another relation.