Couchbase N1QL Keyword Compatibility Reference

Generated for GSP Java version 4.1.0.8 on 2026-03-15

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.

Keyword-as-Column-Name Support

As of version 4.1.0.8, the GSP Couchbase parser includes a lexer lookahead mechanism that allows 12 vendor-unreserved keywords to be used as unquoted column names in SELECT statements.

The lookahead pre-scans the token list before parsing and converts context-specific keywords to identifiers when they appear in column-name position:

• After: SELECT, ,, DISTINCT, or ALL
• Before: FROM, AS, WHERE, GROUP, ORDER, HAVING, LIMIT, UNION, INTERSECT, EXCEPT, INTO, ,, ), or ;

-- Works: keyword as column name
SELECT any FROM t;

-- Works: keyword as column name
SELECT array FROM t;

-- Works: keyword as column name
SELECT case FROM t;

-- Original keyword syntax also still works

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Full Classification Overview

Out of 172 keywords recognized by the GSP Couchbase parser:

Classification	Count	Description
Allowed	156	Can be used as an unquoted column name in both canonical contexts
Context-specific	15	Fails as SELECT keyword FROM t but works as SELECT t.keyword FROM t
Blocked	1	Cannot be used as an unquoted column name in either context

Context-Specific Keywords (15)

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

Keyword	Reason
ALL	SELECT qualifier
ANY	Operator keyword
ARRAY	Type keyword
CASE	Expression keyword
COVER	Grammar keyword
DISTINCT	SELECT qualifier
ELEMENT	Grammar keyword
EVERY	Operator keyword
EXISTS	Operator keyword
FIRST	Grammar keyword
NOT	Operator keyword
OBJECT	Grammar keyword
RAW	Grammar keyword
SOME	Operator keyword
VALUE	Grammar keyword

Blocked Keywords (1)

These keywords cannot be used as unquoted column names in either context.

Keyword	Workaround
FROM	SELECT "from" FROM t

Workaround: Double-Quoted Identifiers

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

-- Blocked or context-specific keyword as column name
SELECT "from" FROM t;

-- Or use table qualification for context-specific keywords
SELECT t.all FROM t;

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 4.1.0.8.
• 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 Couchbase

Methodology

1. Static extraction: A Python script parses the lexer (.cod) and grammar (.y) source files to identify all 172 keywords and their grammar classifications.
2. Runtime validation: A Java test harness validates every classification against actual TGSqlParser runtime behavior.
3. JSON dataset: The authoritative data is stored in docs/generated/couchbase_keyword_compatibility.json.