BSON_VALUE_DOUBLE function

The BSON_VALUE_DOUBLE function is a built-in SQL function that numeric values in a BSON field to the DOUBLE PRECISION data type. The function returns string values that require eight bytes of storage.

Use the BSON_VALUE_DOUBLE function to return or operate on numeric data in a field in a BSON column with SQL statements.

Syntax

BSON_VALUE_DOUBLE function

>>-BSON_VALUE_DOUBLE--(--bson_column--,--"--field--"--)--------><


Element	Description	Restrictions	Syntax
`bson_column`	Name of a BSON column	Must exist	Identifier
`field`	A string that represents a field name to search for in the BSON column. Can be a multilevel identifier.		Quoted String, Column Expressions

Usage

The field parameter can be a simple SQL identifier. The statements in the following example create a table with a BSON column, insert three documents, and then return the value of the id field. The documents are explicitly cast to JSON and then implicitly cast to BSON.

CREATE DATABASE testdb WITH LOG;
CREATE TABLE IF NOT EXISTS bson_table(bson_col BSON);

INSERT INTO bson_table VALUES('{id:7000,veritas:"t"}'::JSON);
INSERT INTO bson_table VALUES('{id:7001,veritas:"f"}'::JSON);
INSERT INTO bson_table VALUES('{id:7002,veritas:"t"}'::JSON);

SELECT BSON_VALUE_DOUBLE(bson_col,"id") FROM bson_table;

     (expression)   
             7000.000000000
             7001.000000000
             7002.000000000

3 row(s) retrieved.

This example shows simple field-name value pairs, but the field parameter in BSON_VALUE_DOUBLE expressions for BSON columns with more complex structures can be specified as a multilevel identifier in dot notation.