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.

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.
• Expected Column expression, but got
• Invalid LIKE pattern
• Only SELECT statements with WHERE clause are supported. The…

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

Appendix: 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(

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