# substring — DuckDB 1.4.4 Extracts substring starting from character `start` up to the end of the string. If optional argument `length` is set, extracts a substring of `length` characters instead. Note that a `start` value of `1` refers to the first character of the `string`. - Reference: /products/haybarn/functions/releases/duckdb-1.4.4/substring/ - JSON: /products/haybarn/functions/api/v1/duckdb-1.4.4/functions/substring.json - Snapshot ID: duckdb-1.4.4 - Engine: duckdb v1.4.4 - Source ID: 6ddac802ff - Binary SHA-256: 8d05bee013ea13d6b5d75272d7ddb52b3d6d9cdaf30d1a3e8e82d42757905182 - Captured: 2026-09-05T18:37:36.091Z - Source: https://github.com/duckdb/duckdb/releases/tag/v1.4.4 - Loaded extensions: autocomplete, core_functions, icu, json, parquet, shell ## Interpretation - Choose a snapshot matching the target engine and build. The default is captured from the published Haybarn WASM package used by the browser playground. Historical native snapshots are also available. - Availability is an observation in the recorded build and extension profile, not a guarantee of support in every installation or in WASM. - Types and descriptions are declarations from duckdb_functions(). Binding can specialize result types. Null means not supplied by the catalog; do not invent defaults, optionality, argument mode, or table output columns. - Raw parameter arrays preserve catalog order for scalar/aggregate/macro functions. Raw table arguments are alphabetical. Use callingConvention for engine-confirmed positional order and named arguments; null modes are unrecorded. Named does not mean optional. Macro defaults and special named variadic behavior are not supplied by duckdb_functions(). - Catalog examples are source material and may require data or extensions. runnableExamples contains separately verified SQL for the pinned WASM package; sample-data adaptations and guide examples are labeled separately. - Guide annotations and recipes are separate editorial content. The browser runner always uses Haybarn WASM 1.5.5-rc3, independently of the documentation snapshot. - All URLs beginning with / are relative to the origin hosting this document. Exports require no JavaScript, cookies, API key, or browser engine. ## Overloads ### overload-43dc9fdbd2f59711 Kind: scalar. Parameter order: catalog-order. ```text substring(string: VARCHAR, start: BIGINT) → VARCHAR ``` Link: /products/haybarn/functions/releases/duckdb-1.4.4/substring/#overload-43dc9fdbd2f59711 | Argument | Catalog type | Calling mode | | --- | --- | --- | | string | VARCHAR | not recorded | | start | BIGINT | not recorded | Declared return type: VARCHAR. Variadic argument type: none declared. Stability: CONSISTENT. Declared side effects: false. ### overload-bbffa3e2c5614444 Kind: scalar. Parameter order: catalog-order. ```text substring(string: VARCHAR, start: BIGINT, length: BIGINT) → VARCHAR ``` Link: /products/haybarn/functions/releases/duckdb-1.4.4/substring/#overload-bbffa3e2c5614444 | Argument | Catalog type | Calling mode | | --- | --- | --- | | string | VARCHAR | not recorded | | start | BIGINT | not recorded | | length | BIGINT | not recorded | Declared return type: VARCHAR. Variadic argument type: none declared. Stability: CONSISTENT. Declared side effects: false. ## Guide recipes No guide recipes. ## Engine catalog examples Source examples may require additional data or extensions. Expressions are wrapped in SELECT; execution verification is not recorded. Reported for: overload-43dc9fdbd2f59711, overload-bbffa3e2c5614444 ```sql SELECT substring('Hello', 2); ``` Reported for: overload-43dc9fdbd2f59711, overload-bbffa3e2c5614444 ```sql SELECT substring('Hello', 2, 2); ``` ## Runnable examples Executed successfully in Haybarn WASM 1.5.5-rc3. Sample data and guide examples are separate from the original catalog. ```sql SELECT substring('Hello', 2); ``` ```sql SELECT substring('Hello', 2, 2); ``` ## Additional DuckDB documentation - [Text Functions](https://duckdb.org/docs/current/sql/functions/text#substringstring-start-length) - [Text Functions](https://duckdb.org/docs/current/sql/functions/text.html#substringstring-start-length) ## In other engines ### Amazon Redshift: regexp_substr() Uses substring as part of a larger rewrite. Amazon Redshift: ```sql SELECT REGEXP_SUBSTR(abc, 'pattern(group)', 2) FROM table ``` Haybarn / DuckDB: ```sql SELECT REGEXP_EXTRACT(SUBSTRING(abc, 2), 'pattern(group)') FROM "table" ``` Translation from [SQLGlot](https://github.com/tobymao/sqlglot/blob/3086608e6fd4c41c02dfba47171608d2b193fce2/tests/dialects/test_redshift.py#L811). ### Apache Hive: locate() Uses substring as part of a larger rewrite. Apache Hive: ```sql LOCATE('a', x, 3) ``` Haybarn / DuckDB: ```sql CASE WHEN STRPOS(SUBSTRING(x, 3), 'a') = 0 THEN 0 ELSE STRPOS(SUBSTRING(x, 3), 'a') + 3 - 1 END ``` Translation from [SQLGlot](https://github.com/tobymao/sqlglot/blob/3086608e6fd4c41c02dfba47171608d2b193fce2/tests/dialects/test_hive.py#L702). ### BigQuery: regexp_extract() Uses substring as part of a larger rewrite. BigQuery: ```sql SELECT REGEXP_EXTRACT(abc, 'pattern(group)', 2) FROM table ``` Haybarn / DuckDB: ```sql SELECT REGEXP_EXTRACT(NULLIF(SUBSTRING(abc, 2), ''), 'pattern(group)', 1) FROM "table" ``` Translation from [SQLGlot](https://github.com/tobymao/sqlglot/blob/3086608e6fd4c41c02dfba47171608d2b193fce2/tests/dialects/test_bigquery.py#L3161). ### Presto Uses substring as part of a larger rewrite. Presto: ```sql DATE_PARSE(SUBSTR(x, 1, 10), '%Y-%m-%d') ``` Haybarn / DuckDB: ```sql STRPTIME(SUBSTRING(x, 1, 10), '%Y-%m-%d') ``` Translation from [SQLGlot](https://github.com/tobymao/sqlglot/blob/3086608e6fd4c41c02dfba47171608d2b193fce2/tests/dialects/test_presto.py#L344). ### Snowflake: regexp_replace() Snowflake: ```sql REGEXP_REPLACE(subject, pattern, replacement, 3, 1) ``` Haybarn / DuckDB: ```sql SUBSTRING(subject, 1, 2) || REGEXP_REPLACE(SUBSTRING(subject, 3), pattern, replacement) ``` Translation from [SQLGlot](https://github.com/tobymao/sqlglot/blob/3086608e6fd4c41c02dfba47171608d2b193fce2/tests/dialects/test_snowflake.py#L5245). ## Observed availability | Snapshot | Observed | Overloads | JSON | | --- | --- | --- | --- | | haybarn-1.5.5-rc3 | present | 2 | [reference](/products/haybarn/functions/api/v1/haybarn-1.5.5-rc3/functions/substring.json) | | duckdb-1.5.5 | present | 2 | [reference](/products/haybarn/functions/api/v1/duckdb-1.5.5/functions/substring.json) | | duckdb-1.4.4 | present | 2 | [reference](/products/haybarn/functions/api/v1/duckdb-1.4.4/functions/substring.json) | | duckdb-1.3.2 | present | 2 | [reference](/products/haybarn/functions/api/v1/duckdb-1.3.2/functions/substring.json) | Engine catalog documentation is derived from MIT-licensed Haybarn and DuckDB. [Notices](/third-party-notices.txt).