return queryBlockFromIsNull(visitor, query, true);
}
public static boolean queryBlockFromIsNull(WallVisitor visitor, SQLSelectQuery query, boolean checkSelectConst) {
if (query instanceof SQLSelectQueryBlock) {
SQLSelectQueryBlock queryBlock = (SQLSelectQueryBlock) query;
SQLTableSource from = queryBlock.getFrom();
if (from == null) {
return true;
}
if (from instanceof SQLExprTableSource) {
SQLExpr fromExpr = ((SQLExprTableSource) from).getExpr();
if (fromExpr instanceof SQLName) {
String name = fromExpr.toString();
name = form(name);
if (name.equalsIgnoreCase("DUAL")) {
return true;
}
}
}
if (queryBlock.getSelectList().size() == 1
&& queryBlock.getSelectList().get(0).getExpr() instanceof SQLAllColumnExpr) {
if (from instanceof SQLSubqueryTableSource) {
SQLSelectQuery subQuery = ((SQLSubqueryTableSource) from).getSelect().getQuery();
if (queryBlockFromIsNull(visitor, subQuery)) {
return true;
}
}
}
if (checkSelectConst) {
SQLExpr where = queryBlock.getWhere();
if (where != null) {
Object whereValue = getValue(visitor, where);
if (Boolean.TRUE == whereValue) {
boolean allIsConst = true;
for (SQLSelectItem item : queryBlock.getSelectList()) {
if (getValue(visitor, item.getExpr()) == null) {
allIsConst = false;
break;
}
}