What causes "Error parsing SQL." in apache/seatunnel?

Print/inspect the SQL string and validate it is a syntactically correct SELECT

apache/seatunnel · error · IllegalArgumentException

Error parsing SQL.

Error message

Error parsing SQL.

What it means

SqlToPaimonPredicateConverter.convertToPlainSelect parses the user-supplied predicate SQL with JSqlParser (CCJSqlParserUtil.parse) and wraps JSQLParserException in IllegalArgumentException('Error parsing SQL.'). It throws when the query string is not syntactically valid SQL the parser understands.

Source

Thrown at seatunnel-connectors-v2/connector-paimon/src/main/java/org/apache/seatunnel/connectors/seatunnel/paimon/source/converter/SqlToPaimonPredicateConverter.java:88

import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Objects;
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.");
        }

View on GitHub (pinned to cf67b549a7)

Solutions

Print/inspect the SQL string and validate it is a syntactically correct SELECT
Simplify the predicate to plain standard SQL (column op value with AND/OR)
Quote identifiers the way JSqlParser accepts (double quotes or consistent backticks)
Test the SQL with JSqlParser directly to reproduce and fix the syntax error

Example fix

// before
String sql = "SELECT * FROM t WHERE date > '2024-01-01' AND status in (1,2")"; // unbalanced
// after
String sql = "SELECT * FROM t WHERE date > '2024-01-01' AND status IN (1, 2)";

Defensive patterns

Strategy: validation

Validate before calling

try { CCJSqlParserUtil.parse(sql); } catch (JSQLParserException e) { throw new IllegalArgumentException("Invalid filter SQL: " + sql, e); }

Try / catch

try { converter.convertToPlainSelect(query); } catch (IllegalArgumentException e) { if (e.getMessage().equals("Error parsing SQL.")) { log.error("Malformed predicate SQL: {}", query); } throw e; }

Prevention

Validate filter SQL with JSqlParser in tests before deploying
Stick to plain standard SQL syntax in predicate strings
Avoid dialect-specific functions and syntax in pushdown filters

When it happens

Trigger: Passing a malformed or dialect-specific SQL predicate string (e.g. a Paimon/MySQL-only syntax, unbalanced quotes, missing WHERE, comments JSqlParser can't handle) to the converter used for Paimon source predicate pushdown.

Common situations: Users writing filter SQL in a dialect JSqlParser doesn't support (backtick vs double-quote mixing, vendor functions); typos in WHERE clauses; empty or whitespace-only fragments slipping past the earlier isBlank check.

Understand the failure class

Background: "query failed", "%w: SQL error" — wrapped database query errors in Go libraries explained — this error's family across 3 libraries.

Related errors

AI-assisted analysis of apache/seatunnel@cf67b549a7 (2026-09-10). Data as JSON: /api/errors/0a593ddf8300ebca. Report an issue: GitHub.