Data only one time in coloum

AppSheet AppSheet Q&A
,
1

Hello,

if the operator will insert a new serialnumber the app should check that the same serialnumber doen’t exist in the same coloum in a previous row.

How can I do that?

2

Typically you should not user serial number generation system in AppSheet.

Sequential keys - AppSheet Help

On avoiding duplicates , please take a look at the following expression for valid_if of the column as mentioned in the article below.. However even this can fail if two users simultaneously create a / update a record. “Use lists to validate column values”

List expressions - AppSheet Help

ISBLANK(
  FILTER(
    "Table Name",
    ([_THIS] = [Column Name])
  )
  - LIST([_THISROW])
)
2 Likes
3

Thanks very much. It solved my problem too… :grin:
Greets!

1 Like