apache/seatunnel · error · IllegalArgumentException

Only SELECT statements are supported.

Error message

Only SELECT statements are supported.

What it means

After successfully parsing, convertToPlainSelect verifies the Statement is a Select; anything else (INSERT, UPDATE, DELETE, CREATE, etc.) is rejected with IllegalArgumentException('Only SELECT statements are supported.') because the converter only translates SELECT predicates into Paimon predicates.

Source

Thrown at seatunnel-connectors-v2/connector-paimon/src/main/java/org/apache/seatunnel/connectors/seatunnel/paimon/source/converter/SqlToPaimonPredicateConverter.java:92

import java.util.Optional;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class SqlToPaimonPredicateConverter {

    public static PlainSelect convertToPlainSelect(String query) {
        if (StringUtils.isBlank(query)) {
            return null;
        }
        Statement statement = null;
        try {
            statement = CCJSqlParserUtil.parse(query);
        } catch (JSQLParserException e) {
            throw new IllegalArgumentException("Error parsing SQL.", e);
        }
        // Confirm that the SQL statement is a Select statement
        if (!(statement instanceof Select)) {
            throw new IllegalArgumentException("Only SELECT statements are supported.");
        }
        Select select = (Select) statement;
        Select selectBody = select.getSelectBody();
        if (!(selectBody instanceof PlainSelect)) {
            throw new IllegalArgumentException("Only simple SELECT statements are supported.");
        }
        PlainSelect plainSelect = (PlainSelect) selectBody;
        if (plainSelect.getHaving() != null
                || plainSelect.getGroupBy() != null
                || plainSelect.getOrderByElements() != null
                || plainSelect.getLimit() != null) {
            throw new IllegalArgumentException(
                    "Only SELECT statements with WHERE clause are supported. The Having, Group By, Order By, Limit clauses are currently unsupported.");
        }
        return plainSelect;
    }

    public static int[] convertSqlSelectToPaimonProjectionIndex(

View on GitHub (pinned to cf67b549a7)

Solutions

1. Ensure the SQL string is a SELECT statement
2. Use only WHERE-based filter expressions, e.g. 'SELECT * FROM table WHERE col = x'
3. Remove any trailing statements separated by semicolons
4. Strip comments/DDL prefixes from the query string

Example fix

// before
String sql = "DELETE FROM t WHERE id = 1";
// after
String sql = "SELECT * FROM t WHERE id = 1";

String trimmed = sql.trim().toUpperCase(); if (!trimmed.startsWith("SELECT")) throw new IllegalArgumentException("Filter SQL must be a SELECT statement");

try { converter.convertToPlainSelect(query); } catch (IllegalArgumentException e) { if ("Only SELECT statements are supported.".equals(e.getMessage())) { /* fix query to SELECT */ } throw e; }

When it happens

Trigger: Supplying a non-SELECT SQL statement (UPDATE/DELETE/DDL/EXPLAIN) as the predicate/query to the Paimon source predicate converter.

Common situations: Users pasting mutation or DDL statements as filter expressions; tools that build query strings dynamically appending '; DELETE ...'; misunderstanding that the converter is for filter predicates, not arbitrary SQL execution.

Understand the failure class

Background: "Must be a positive integer", "Invalid value", "Unsupported": the invalid-argument-value error family, when a library rejects the value you pass — this error's family across 35 libraries.

Related errors

• Only simple SELECT statements are supported.
• Error parsing SQL.
• Only SELECT statements with WHERE clause are supported. The
• Invalid LIKE pattern: '%s'. Supported patterns are: 'prefix%
• Unsupported expression type: ${expression.getClass().getSimp

AI-assisted analysis of apache/seatunnel@cf67b549a7 (2026-09-10). Data as JSON: /api/errors/e478eb7af5d6636b. Report an issue: GitHub.