Oninit
Talk to an expert →

Informix Error -201: A syntax error has occurred.

Cause and resolution

A syntax error has occurred.

This general error message indicates mistakes in the form of an SQL statement. Look for missing or extra punctuation (such as missing or extra commas, omission of parentheses around a subquery, and so on), keywords misspelled (such as VALEUS for VALUES), keywords misused (such as SET in an INSERT statement or INTO in a subquery), keywords out of sequence (such as a condition of "value IS NOT" instead of "NOT value IS"), or a reserved word used as an identifier.

Database servers that provide full NIST compliance do not reserve any words; queries that work with these database servers might fail and return error -201 when they are used with earlier versions of IBM Informix database servers.

The cause of this error might be an attempt to use round-robin syntax with CREATE INDEX or ALTER FRAGMENT INIT on an index. You cannot use round-robin indexes.

The error may also occur if an SQL statement uses double quotation marks around input strings and the environment variable DELIMIDENT is set. If DELIMIDENT is set, strings that are surrounded by double quotation marks are regarded as SQL identifiers rather than string literals. For more information on the usage of DELIMIDENT, see the IBM Informix Guide to SQL: Reference.

Oninit® Troubleshooting Guidance

Reasons / Common Causes

-201 is one of the most common errors in the entire catalogue — a general-purpose signal that an SQL statement's form is wrong. The official text lists several specific patterns worth checking in order, plus a few less obvious environmental causes that produce the same generic message.

  1. Missing or extra punctuation — a missing or extra comma, omitted parentheses around a subquery, and similar structural mistakes.
  2. Misspelled keywords — VALEUS for VALUES is the official example; any keyword typo produces this same generic error rather than a more specific "unknown keyword" message.
  3. Misused keywords — a keyword valid in SQL generally but wrong for the specific clause it appears in, such as SET in an INSERT statement or INTO inside a subquery where it doesn't belong.
  4. Keywords out of sequence — a condition written as value IS NOT instead of the correct NOT value IS form for certain constructs.
  5. A reserved word used as an identifier without being properly delimited.
  6. NIST-compliance differences. A database created with full NIST compliance may reserve words that aren't reserved otherwise, causing queries that assumed a word was an ordinary identifier to fail — particularly relevant on earlier IBM Informix versions where this behavior might differ from what's expected.
  7. Round-robin fragmentation syntax issues in CREATE INDEX or ALTER FRAGMENT INIT statements — a specific, documented syntax gotcha for that feature.
  8. Double-quoted strings combined with DELIMIDENT. When the DELIMIDENT environment variable is set, double quotes are treated as delimiting an identifier, not a string literal — SQL written assuming double quotes work for string values fails with -201 under that setting.
Solutions / Resolution
  1. Review the statement for missing or extra punctuation first — commas and parentheses around subqueries are the most common culprits.
  2. Check for misspelled keywords — a careful read, or a syntax-highlighting editor, catches these quickly.
  3. Check for keyword misuse — confirm each keyword is valid for the specific clause it appears in, not just valid SQL somewhere.
  4. Check keyword ordering against the correct syntax for the specific construct being used.
  5. If using a reserved word as an identifier, either rename it or delimit it properly (double-quoted, with DELIMIDENT set appropriately).
  6. For NIST-compliant databases, check whether a word assumed to be an ordinary identifier is actually reserved under full NIST compliance mode, especially on older Informix versions.
  7. For round-robin fragmentation syntax, review the exact required CREATE INDEX/ALTER FRAGMENT INIT syntax against current documentation — this specific construct has known gotchas.
  8. Check whether DELIMIDENT is set if double-quoted strings are involved — use single quotes for string literals instead when it is.
Examples
Missing comma
SELECT customer_id customer_name FROM customer;
-- -201: missing comma between customer_id and customer_name
Misspelled keyword
INSERT INTO customer VALEUS (1, 'Jane Doe');
-- -201: VALEUS should be VALUES
Reserved word as an identifier
CREATE TABLE orders (order_id INT, date DATETIME YEAR TO DAY);
-- -201 on some versions: DATE may be reserved — rename the column
-- or delimit it properly
DELIMIDENT and double-quoted strings
-- With DELIMIDENT set:
SELECT * FROM customer WHERE name = "Jane Doe";
-- -201: "Jane Doe" is read as a delimited identifier, not a string literal

-- Fix: use single quotes for the string value
SELECT * FROM customer WHERE name = 'Jane Doe';
Diagnostic Checks
  1. Re-read the statement carefully for punctuation and spelling issues — this resolves the large majority of -201 reports.
  2. Check the DELIMIDENT environment variable if double-quoted strings are involved anywhere in the statement.
  3. Check the database's NIST compliance mode if a seemingly ordinary word is being rejected.
  4. Review round-robin fragmentation syntax against documentation if the failing statement is a CREATE INDEX or ALTER FRAGMENT INIT.
Related Errors / Related Topics
  • -200 — "Identifier is too long." Another general SQL parser-level error, encountered in the same broad category of statement-formation mistakes.

Work through the official guidance's list in order — punctuation, spelling, keyword misuse, keyword ordering, reserved words — before considering the less common environmental causes (DELIMIDENT, NIST compliance, round-robin fragmentation syntax).