BSON_VALUE_OBJECTID function
The BSON_VALUE_OBJECTID function is a built-in SQL function that returns the ObjectId values in a BSON document as strings.
Syntax
BSON_VALUE_OBJECTID function
BSON_VALUE_OBJECTID ( bson_column , " _id " )Element | Description | Restrictions | Syntax |
---|---|---|---|
bson_column | Name of a BSON column | Must exist | Identifier |
Usage
The first field in BSON documents that you create with MongoDB commands is the _id field. The _id field contains a generated ObjectId value that is a unique identifier for the document. Use the BSON_VALUE_OBJECTID function to retrieve ObjectId values as strings.
Example
The following MongoDB command that is run through the wire listener inserts a BSON document into the products table:
"db.products.insert({item:"card", qty:15})"
The following statement returns the entire contents of the products table:
SELECT data::json FROM products;
(expression)
{"_id":ObjectID(54befb9eedbc233cd3a4b2fb"),"item":"card","qty":15.000000}
1 row(s) retrieved.
The following statement returns the ObjectID value from the products table:
SELECT BSON_VALUE_OBJECTID(data,"_id") FROM products;
(expression) 54befb9eedbc233cd3a4b2fb
1 row(s) retrieved.