Convert SQL query into mongodb

Question

What is the MongoDB equivalent for the following SQL query?

SELECT
  station_id,
  group_concat('signals')
FROM signals
GROUP BY station_id

i need to group by "station id", and concat "signal", thanks, the result would be like that:

| station_id | signals |
     321       2,3,5,2

jsoneditoronline.org/?id=9bfba1557ddd40ca9db67fd2038ad923, i need to group by "station id", and concat "signal", thanks — Alex
– Alex, Commented Dec 9, 2019 at 7:24
jsoneditoronline.org/?id=9bfba1557ddd40ca9db67fd2038ad923 - There are three documents here — Alex
– Alex, Commented Dec 9, 2019 at 7:33

Rubin Porwal · Accepted Answer · 2019-12-09 07:37:51Z

1

Please refer following aggregate query as an equivalent query of SQL into Mongodb

db.signals.aggregate(

    // Pipeline
    [
        // Stage 1
        {
            $group: {
                _id: '$station_id',
                signals: {
                    $push: '$signal'
                }
            }
        },

    ]

);

answered Dec 9, 2019 at 7:37

Rubin Porwal

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