title	titleSuffix	description	author	ms.author	ms.reviewer	ms.service	ms.subservice	ms.topic	ms.devlang	ms.date	ms.custom
LOWER	Azure Cosmos DB for NoSQL	An Azure Cosmos DB for NoSQL system function that returns a string expression with uppercase characters converted to lowercase.	jcodella	jacodel	sidandrews	cosmos-db	nosql	reference	nosql	02/27/2024	query-reference

LOWER (NoSQL query)

[!INCLUDENoSQL]

Returns a string expression after converting uppercase character data to lowercase.

Note

This function automatically uses culture-independent (invariant) casing rules when returning the converted string expression.

Syntax

LOWER(<string_expr>)

	Description
`string_expr`	A string expression.

Returns a string expression.

The following example shows how to use the function to modify various strings.

:::code language="nosql" source="~/cosmos-db-nosql-query-samples/scripts/lower/query.sql" highlight="2-6":::

:::code language="json" source="~/cosmos-db-nosql-query-samples/scripts/lower/result.json":::

This function doesn't use the index.
If you plan to do frequent case insensitive comparisons, this function may consume a significant number of RUs. Consider normalizing the casing of strings when ingesting your data. Then a query like SELECT * FROM c WHERE LOWER(c.name) = 'USERNAME' is simplified to SELECT * FROM c WHERE c.name = 'USERNAME'.