SQL Text
 └─Statements: net.sf.jsqlparser.statement.select.Select
    └─selectBody: net.sf.jsqlparser.statement.select.PlainSelect
       ├─selectItems -> Collection<SelectExpressionItem>
       │  └─selectItems: net.sf.jsqlparser.statement.select.SelectExpressionItem
       │     └─LongValue: 1
       ├─Table: dual
       └─where: net.sf.jsqlparser.expression.operators.relational.EqualsTo
          ├─Column: a
          └─Column: b

Statement statement = CCJSqlParserUtil.parse(sqlStr);
if (statement instanceof Select) {
    Select select = (Select) statement;
    PlainSelect plainSelect = (PlainSelect) select.getSelectBody();

    SelectExpressionItem selectExpressionItem =
            (SelectExpressionItem) plainSelect.getSelectItems().get(0);

    Table table = (Table) plainSelect.getFromItem();

    EqualsTo equalsTo = (EqualsTo) plainSelect.getWhere();
    Column a = (Column) equalsTo.getLeftExpression();
    Column b = (Column) equalsTo.getRightExpression();
}