pg_sqlparser

An sql parser that parses PostgreSQL to Java objects

Sometimes it may be handy to be able to parse (PostgreSQL) sql statements into Java objects. pg_sqlparser does that.

The parser is generated directly from the actual PostgreSQL parser sources, so the implementation should come pretty close to what PostgreSQL does itself.

Features

• Parses PostgreSQL sql statements to a Java object structure
• Can visualise the parsed structure in an XML structure
• Can generate sql statements from the Java object structure
• Comes with a test GUI to visualise the three features above

Prerequisites

• Java 11 or higher
• Maven 3.5.2 or higher
• Bison 3.0 or higher

Usage

Here is an example of how to use the parser:

   ...
public static void main(String[] args) {
    String sql = "SELECT a, sum(b) AS total "
               + "FROM tbl "
               + "WHERE a != 'excl' "
               + "GROUP BY a";
    List<SqlParserErrorData> parserErrors = new ArrayList<>();
    try (Reader reader = new StringReader(sql)) {
        SqlParser parser = new SqlParser(reader
                                        , error -> parserErrors.add(error)
                                        );
        if (parser.parse()) {
            for (Node parsedStatement : parser.getResult()) {
                System.out.println("The parsed statement = "
                                  + parsedStatement
                                  );
                System.out.println(
                        "The statement in XML format looks like:\n"
                        + ParserUtil.stmtToXml(parsedStatement)
                        );
            }
        } else {
            for (SqlParserErrorData err : parserErrors) {
                System.out.println("Parser error: " + err);
            }
        }
    } catch (IOException e) {
        System.out.println(e);
    }
}
   ...

More information can be found in https://github.com/splendiddata/pg_sqlparser/tree/main/doc/README.pdf

Branches

The Postgres_13 branch contains a parser based on the PostgreSQL 13 parser.
The Postgres_14 branch contains a parser based on the PostgreSQL 14 parser.
The Postgres_15 branch contains a parser based on the PostgreSQL 15 parser.
The Postgres_16 branch contains a parser based on the PostgreSQL 16 parser.
The main branch is based on the PostgreSQL 17 parser.