LOWER_ATTRIBUTE_NAMES function - Amazon Redshift
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Converts all applicable attribute names in a SUPER value to lowercase, using the same case conversion routine as the LOWER function. LOWER_ATTRIBUTE_NAMES supports UTF-8 multibyte characters, up to a maximum of four bytes per character.

To convert SUPER attribute names to uppercase, use the UPPER_ATTRIBUTE_NAMES function.





A SUPER expression.

Return type


Usage notes

In Amazon Redshift, column identifiers are traditionally case-insensitive and converted to lowercase. If you ingest data from case-sensitive data formats such as JSON, the data might contain mixed-case attribute names.

Consider the following example.

CREATE TABLE t1 (s) AS SELECT JSON_PARSE('{"AttributeName": "Value"}'); SELECT s.AttributeName FROM t1; attributename ------------- NULL SELECT s."AttributeName" FROM t1; attributename ------------- NULL

Amazon Redshift returns NULL for both queries. To query AttributeName, use LOWER_ATTRIBUTE_NAMES to convert the data’s attribute names to lowercase. Consider the following example.

CREATE TABLE t2 (s) AS SELECT LOWER_ATTRIBUTE_NAMES(s) FROM t1; SELECT s.attributename FROM t2; attributename ------------- "Value" SELECT s.AttributeName FROM t2; attributename ------------- "Value" SELECT s."attributename" FROM t2; attributename ------------- "Value" SELECT s."AttributeName" FROM t2; attributename ------------- "Value"

A related option for working with mixed-case object attribute names is the enable_case_sensitive_super_attribute configuration option, which lets Amazon Redshift recognize case in SUPER attribute names. This can be an alternative solution to using LOWER_ATTRIBUTE_NAMES. For more information about enable_case_sensitive_super_attribute, go to enable_case_sensitive_super_attribute.


Converting SUPER attribute names to lowercase

The following example uses LOWER_ATTRIBUTE_NAMES to convert the attribute names of all SUPER values in a table.

-- Create a table and insert several SUPER values. CREATE TABLE t (i INT, s SUPER); INSERT INTO t VALUES (1, NULL), (2, 'A'::SUPER), (3, JSON_PARSE('{"AttributeName": "B"}')), (4, JSON_PARSE( '[{"Subobject": {"C": "C"}, "Subarray": [{"D": "D"}, "E"] }]')); -- Convert all attribute names to lowercase. UPDATE t SET s = LOWER_ATTRIBUTE_NAMES(s); SELECT i, s FROM t ORDER BY i; i | s ---+-------------------------------------------------- 1 | NULL 2 | "A" 3 | {"attributename":"B"} 4 | [{"subobject":{"c":"C"},"subarray":[{"d":"D"}, "E"]}]

Observe how LOWER_ATTRIBUTE_NAMES functions.

  • NULL values and scalar SUPER values such as "A" are unchanged.

  • In a SUPER object, all attribute names are changed to lowercase, but attribute values such as "B" remain unchanged.

  • LOWER_ATTRIBUTE_NAMES applies recursively to any SUPER object that is nested inside a SUPER array or inside another object.

Using LOWER_ATTRIBUTE_NAMES on a SUPER object with duplicate attribute names

If a SUPER object contains attributes whose names differ only in their case, LOWER_ATTRIBUTE_NAMES will raise an error. Consider the following example.

SELECT LOWER_ATTRIBUTE_NAMES(JSON_PARSE('{"A": "A", "a": "a"}')); error: Invalid input code: 8001 context: SUPER value has duplicate attributes after case conversion.