How to log SQL query of the collection?

Question

I want to log the SQL query for a custom collection. I tried the following code. But did not work. Any suggestions will be appreciated.

Mage::log($collection->getSelect(),null,'test.log',true);

Answer 1

If you want the SQL query from a collection you need to cast it as string. Just add (string) to your previously written logging code.

Mage::log((string)$collection->getSelect(),null,'test.log',true);

Answer 2

Try out $Collection->printLogQuery(true); this will print collection query.

Answer 3

As Flyingmana explained to me, thanks to him.

$collection->load($printQuery = false, $logQuery = false)

It is important to log or print the query after the loading, because in the beforeLoad method can lot of thing be done. So the first answer:

Mage::log((string)$collection->getSelect(),null,'test.log',true);

should be used AFTER load is called.

Answer 4

Step 1:

$result_colletion = print_r($collection->getSelect());
Mage::log($$result_colletion, null, custom_collection.log,true);

Step 2: After that Login into Magento admin section and enable to log setting . Please see below .

System > Configuration > Developer > Log Settings

Step 3: After that see the log file “custom_collection.log” in var/log/ folder .

Answer 5

Mage::log($collection->getSelect()->__toString(), Zend_Log::DEBUG, 'test.log', true);

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Edit:

Instead of using null (fallback to DEBUG) as second parameter better use one of these from Zend_Log:

const EMERG   = 0;  // Emergency: system is unusable
const ALERT   = 1;  // Alert: action must be taken immediately
const CRIT    = 2;  // Critical: critical conditions
const ERR     = 3;  // Error: error conditions
const WARN    = 4;  // Warning: warning conditions
const NOTICE  = 5;  // Notice: normal but significant condition
const INFO    = 6;  // Informational: informational messages
const DEBUG   = 7;  // Debug: debug messages