List Dereference Automated Sequential Number

AppSheet AppSheet Q&A
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1

Hi, I require something very simple, I have a dereference list, with repeated events.
Im recording Drone operations. The first value record de the date, location, etc of the event.
And there is a dereference list, recording the time of each flight.
Im looking for an expression for a column filled automatically with sequential numbers, 1, 2, 3, 4… etc. starting from the first flight, as 1. Appsheet sort each event in the dereference list, according the time of creation, But I can not figure out the expression in how to fill a new column printing the sequence number. Thanks in advance!

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I see two things here. One is about sequential. Another is about sort order.

Sequential:

[Serial Numbers, If You Must](https://community.appsheet.com/t/serial-numbers-if-you-must/19325) Tips & Tricks ?

Danger Ahead! In general, sequential numeric identifiers (i.e., serial numbers) are risky in AppSheet: if two users happen to add rows at the same time, both rows could be assigned the same serial number, which could lead to confusion (at the least) or data loss (at the worst). For this reason, serial numbers are strongly discouraged! Basic Serial Numbers One way to implement serial numbers is with a normal (not virtual) column named (e.g.) Serial of type Number and an Initial value expression …

Sorting:

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Thank you SkrOYC.
Since is a dereferred list, i guess the danger with serial numbers could be avoided, since there is a uniqueID, that relates the record of two different users.
I still can not figure out how to generate the expression in this case, because, for each new record, the serial number should restart in the value 1.

4

Inao_Vasquez:

for each new record, the serial number should restart in the value 1.

“New” in the context of the values inside the Inline View?
I mean, there are going to be multiple 1, 2, 3 but for diferent [Related something], right?

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5

Right, there are going to be multiple 1, 2, 3 but for different related ID

6

Tell us the column name of the Ref column that holds the key value of the parent table and I’ll post an expression to you
Also the table name of the child records and it’s Key column

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7

So kind from you!

“column name of the Ref column that holds the key value of the parent table”: [Id Servicio]
“table name of the child records”: [Vuelos]
Key column of [Vuelos]: [_RowNumber]

Thanks a lot for your responses

8

Veo que hablas español.
Antes de postear alguna fórmula, creo que deberías chequear tu configuración.
Usar [_RowNumber] como key es una pésima idea que te provocará problemas.
En general, siempre crea una columna físicamente en tus tablas (generalmente al inicio, la primera columna) y configura dentro de AppSheet que su Initial Value sea UNIQUEID()

Esta es la fórmula que debe ir como Initial Value en la columna que necesitas que tenga un número secuencial

COUNT(
  FILTER(
    "VUELOS",
    [ID SERVICIO]=[_THISROW].[ID SERVICIO]
  )
)+1
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Funcionó perfecto Oscar!!! fino!!
un abrazooo muchas mil gracias

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Recuerda arreglar lo antes que puedas lo de la llave.
Te dejo info al respecto:

Row Number Keys> > If you do not specify a key, and AppSheet cannot automatically find a good key, AppSheet will default to using the worksheet row number as the key. The row number is not a good key. If entries are moved or deleted, or if users add or delete entries simultaneously, the row number for each row will change and there is no way for AppSheet to uniquely identify the row. The Editor will give a warning if row number is chosen as the key.

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11

Siii muchas gracias!!

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