Examples with ExpressionList net.sf.jsqlparser.expression.operators.relational.ExpressionList used on opensource projects

Example 21 with ExpressionList

use of net.sf.jsqlparser.expression.operators.relational.ExpressionList in project dbeaver by dbeaver.

the class SQLQueryTransformerCount method tryInjectCount.

private SQLQuery tryInjectCount(DBPDataSource dataSource, SQLQuery query) throws DBException {
    try {
        Statement statement = CCJSqlParserUtil.parse(query.getText());
        if (statement instanceof Select && ((Select) statement).getSelectBody() instanceof PlainSelect) {
            PlainSelect select = (PlainSelect) ((Select) statement).getSelectBody();
            if (select.getHaving() != null) {
                throw new DBException("Can't inject COUNT into query with HAVING clause");
            }
            if (select.getGroupBy() != null && !CommonUtils.isEmpty(select.getGroupBy().getGroupByExpressions())) {
                throw new DBException("Can't inject COUNT into query with GROUP BY clause");
            }
            Distinct selectDistinct = select.getDistinct();
            if (selectDistinct != null) {
                // Remove distinct
                select.setDistinct(null);
            }
            Function countFunc = new Function();
            countFunc.setName("count");
            if (selectDistinct != null) {
                countFunc.setDistinct(true);
                List<Expression> exprs = new ArrayList<>();
                for (SelectItem item : select.getSelectItems()) {
                    if (item instanceof SelectExpressionItem) {
                        exprs.add(((SelectExpressionItem) item).getExpression());
                    }
                }
                if (!exprs.isEmpty()) {
                    countFunc.setParameters(new ExpressionList(exprs));
                }
            }
            countFunc.setAllColumns(true);
            List<SelectItem> selectItems = new ArrayList<>();
            selectItems.add(new SelectExpressionItem(countFunc));
            select.setSelectItems(selectItems);
            select.setOrderByElements(null);
            return new SQLQuery(dataSource, select.toString(), query, false);
        } else {
            throw new DBException("Query [" + query.getText() + "] can't be modified");
        }
    } catch (JSQLParserException e) {
        throw new DBException("Can't transform query to SELECT count(*)", e);
    }
}