Select count

[Dana Borger <Da...@sas.com>]

When selecting a count from a query result is there a better way than this? For example, I’m seeing Postgres return a Long and Oracle return a BigDecimal, so always casting to Long is no good.

        Query q = new Query().
        q.from(“mytable”);
        q.selectCount();   // SELECT COUNT(*) FROM “mytable”;

        …

try (DataSet dataSet = dataContext.executeQuery(q)) {
    if (dataSet.next()) {
        Row r = dataSet.getRow();
        for (SelectItem item : r.getSelectItems()) {
            Object N = r.getValue(item);
            if (N instanceof Number) {
                long count = ((Number)N).longValue());
            }
            else {
                ...
            }
        }
    }
}

Thanks!
db

Re: Select count

[Kasper Sørensen <i....@gmail.com>]

I always just go ahead and cast it to Number without instanceof checking
TBH. All the cases that I know of are some subclass of Number.

2017-07-29 5:30 GMT-07:00 Dana Borger <Da...@sas.com>:

>
>
> When selecting a count from a query result is there a better way than this?
> For example, I’m seeing Postgres return a Long and Oracle return a
> BigDecimal, so always casting to Long is no good.
>
>
>
>         Query q = new Query().
>
>         q.from(“mytable”);
>
>         q.selectCount();   // SELECT COUNT(*) FROM “mytable”;
>
>
>
>         …
>
>
>
> try (DataSet dataSet = dataContext.executeQuery(q)) {
>
>     if (dataSet.next()) {
>
>         Row r = dataSet.getRow();
>
>         for (SelectItem item : r.getSelectItems()) {
>
>             Object N = r.getValue(item);
>
>             if (N instanceof Number) {
>
>                 long count = ((Number)N).longValue());
>
>             }
>
>             else {
>
>                 ...
>
>             }
>
>         }
>
>     }
>
> }
>
>
>
> Thanks!
>
> db
>
>
>