Calcite #

public static RelRoot genRelRoot(Connection connection, String sql) throws Exception {
    //从 conn 中获取相关的环境和配置，生成对应配置
    CalciteServerStatement st = connection.createStatement().unwrap(CalciteServerStatement.class);
    CalcitePrepare.Context prepareContext = st.createPrepareContext();
    final FrameworkConfig config = Frameworks.newConfigBuilder()
            .parserConfig(SqlParser.configBuilder().setLex(Lex.MYSQL).build())
            .defaultSchema(prepareContext.getRootSchema().plus())
//                .traitDefs(ConventionTraitDef.INSTANCE, RelDistributionTraitDef.INSTANCE)
            .build();
    Planner planner = Frameworks.getPlanner(config);
    RelRoot root = null;
    try {
        // 解析
        SqlNode parse1 = planner.parse(sql);
        // 校验
        SqlNode validate = planner.validate(parse1);
        root = planner.rel(validate);
        RelNode rel = root.rel;
    } catch (Exception e) {
        e.printStackTrace();
    }

    return root;
}