MongoDB嵌套$ or查询

Question

Example of a Mongo Entry:

array(
    'name' => 'blog one',
    'blogCategory' => array(
        'displayAndLightMeasurement' => '1',
        'LEDAndDisplayTestInstrument' => '0'
    )
);

A Query like this works fine:

$blogInfoRaw = $collection->find(array('blogCategory' => array('displayAndLightMeasurement' => '1')));

When I try to '$or' query like this:

$blogInfoRaw = $collection->find(array('$or' => array('blogCategory' => array('displayAndLightMeasurement' => '1')),array('blogCategory' => array('LEDAndDisplayTestInstrument' => '1'))));

I get this error:

$or requires nonempty array

What am I doing wrong?

Answer 1

You really meant to use "dot notation" to reference the embedded fields:

$blogInfoRaw = $collection->find(
    array(
       '$or' => array(
           array( 'blogCategory.displayAndLightMeasurement' => '1' ),
           array( 'blogCategory.LEDAndDisplayTestInstrument' => '1')
       )
    )
);

Otherwise the notation you are using implies that the "only" elements present in the embedded level are those that you specify. This is not true since there are multiple keys. So "dot notation" solves this problem by referencing the distinct keys.

PHP array notation does not help here, but the $or needs to be a wrapping "real" array as in [] also.

Issuing a json_encode often helps when comparing to the official MongoDB examples.