Redshift Keyword Compatibility Reference

Generated for GSP Java version 4.1.0.7 on 2026-03-13

This page was generated using hybrid static extraction from parser source files combined with runtime validation against the actual GSP parser. Re-run the extraction script after parser updates to keep this page current.

Keywords That AWS Allows but GSP Restricts

The following 6 keywords can be used as unquoted column names in AWS Redshift (they are not on the AWS reserved words list), but the GSP parser currently restricts their use:

Keyword	GSP Behavior	Example That Fails	Workaround
LISTAGG	Blocked — fails in all contexts	SELECT listagg FROM t	SELECT "listagg" FROM t
APPROXIMATE	Context-specific — fails unqualified	SELECT approximate FROM t	SELECT t.approximate FROM t or SELECT "approximate" FROM t
CHARACTER	Context-specific — fails unqualified	SELECT character FROM t	SELECT t.character FROM t or SELECT "character" FROM t
CONNECT_BY_ROOT	Context-specific — fails unqualified	SELECT connect_by_root FROM t	SELECT t.connect_by_root FROM t or SELECT "connect_by_root" FROM t
CONVERT	Context-specific — fails unqualified	SELECT convert FROM t	SELECT t.convert FROM t or SELECT "convert" FROM t
DOUBLE	Context-specific — fails unqualified	SELECT double FROM t	SELECT t.double FROM t or SELECT "double" FROM t

"Context-specific" means SELECT keyword FROM t fails but SELECT t.keyword FROM t succeeds. The parser misinterprets the bare keyword as part of SQL syntax rather than a column name.

These 6 keywords are candidates for future grammar relaxation. If you encounter issues with any of them, use the workarounds above or report through your support channel.

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Full Classification Overview

Out of 488 keywords recognized by the GSP Redshift parser:

Classification	Count	Description
Allowed	457	Can be used as an unquoted column name in both canonical contexts
Context-specific	29	Fails as SELECT keyword FROM t but works as SELECT t.keyword FROM t
Blocked	2	Cannot be used as an unquoted column name in either context

Of the 29 context-specific and 2 blocked keywords, 25 are also reserved by AWS Redshift — so they would cause issues in AWS Redshift as well. Only the 6 keywords listed above represent a gap between GSP and AWS behavior.

Context-Specific Keywords (Full List)

These keywords fail when used as bare column names (SELECT keyword FROM t) but succeed when table-qualified (SELECT t.keyword FROM t).

Keyword	Also Reserved by AWS?	Reason
ALL	Yes	SELECT qualifier (SELECT ALL)
APPROXIMATE	No	Parsed as APPROXIMATE COUNT syntax
ARRAY	Yes	Type/expression keyword
AUTHORIZATION	Yes	Privilege keyword
BINARY	Yes	Type keyword
CASE	Yes	Starts CASE expression
CAST	Yes	Starts CAST expression
CHARACTER	No	Type keyword
CONNECT_BY_ROOT	No	Hierarchical query keyword
CONVERT	No	Starts CONVERT expression
CROSS	Yes	JOIN keyword
DISTINCT	Yes	SELECT qualifier
DOUBLE	No	Type keyword (DOUBLE PRECISION)
FREEZE	Yes	Join keyword
FULL	Yes	JOIN keyword
ILIKE	Yes	Operator keyword
INNER	Yes	JOIN keyword
INTO	Yes	SELECT INTO keyword
IS	Yes	Operator keyword
JOIN	Yes	JOIN keyword
LEFT	Yes	JOIN keyword
LIKE	Yes	Operator keyword
NATURAL	Yes	JOIN keyword
OUTER	Yes	JOIN keyword
OVERLAPS	Yes	Operator keyword
RIGHT	Yes	JOIN keyword
SIMILAR	Yes	Operator keyword
TOP	Yes	SELECT TOP N clause
VERBOSE	Yes	Modifier keyword

Blocked Keywords (Full List)

Keyword	Also Reserved by AWS?	Workaround
FROM	Yes	SELECT "FROM" FROM t
LISTAGG	No	SELECT "LISTAGG" FROM t

The POSITION Keyword

The POSITION keyword is a notable dual-use case. Following a customer-reported bug (MantisBT #4360), it was moved from collabel_reserved_keyword to keyword_canbe_column_name, allowing it to function both as:

• A column name: SELECT position FROM t
• A function: SELECT POSITION('a' IN 'abc') FROM t

Both uses parse correctly in the current version.

Workaround: Double-Quoted Identifiers

For any keyword that fails as an unquoted column name, you can use double-quoted identifiers:

-- Blocked keyword as column name: fails
SELECT listagg FROM t;

-- Workaround: quote the identifier
SELECT "listagg" FROM t;

-- Context-specific keyword: fails unqualified
SELECT convert FROM t;

-- Workarounds
SELECT t.convert FROM t;  -- table-qualified
SELECT "convert" FROM t;  -- double-quoted

Double-quoted identifiers have been verified to work for all blocked and context-specific keywords listed on this page.

Scope and Limitations

• Tested contexts: SELECT keyword FROM t and SELECT t.keyword FROM t. Other contexts (DDL column definitions, INSERT column lists, aliases) may behave differently.
• Version-specific: This report reflects GSP Java version 4.1.0.7.
• AWS comparison: Based on the AWS Redshift reserved words list dated 2023-05-08. AWS may have updated their list since.
• Case sensitivity: Keywords are case-insensitive. select, SELECT, and Select are all treated the same.

How to Report Discrepancies

If you encounter a keyword that behaves differently from what this page describes, please report it through your support channel. Include:

1. The exact SQL statement
2. The GSP parser version
3. Whether the same SQL works in Amazon Redshift

Methodology

1. Static extraction: A Python script parses the lexer (.cod) and grammar (.y) source files to identify all 488 keywords and their grammar classifications.
2. Runtime validation: A Java test harness validates every classification against actual TGSqlParser runtime behavior.
3. AWS comparison: The runtime-verified GSP classifications are compared against the AWS Redshift reserved words list to identify gaps.
4. JSON dataset: The authoritative data is stored in docs/generated/redshift_keyword_compatibility.json.