Write a query in XQuery on the XML representation as shown below to compute the left outer join of customer elements with account elements. 

<!DOCTYPE bank-2 [

<!ELEMENT account ( branch, balance )>

<!ATTLIST account

account-number ID #REQUIRED

owners IDREFS #REQUIRED >

<!ELEMENT customer ( customer-name, customer-street, customer-city )>

<!ATTLIST customer

customer-id ID #REQUIRED

accounts IDREFS #REQUIRED >

· · · declarations for branch, balance, customer-name,

customer-street and customer-city · · · ] >