Multi Select Picklist field VR

Question

Is it possible to create a Validation rule or something on multi select picklist field so that the user can select maximum of 3 and minimum of 1 values out of 10.

Answer 1

It's a bit of a hack, but you could try something like this where you would include an argument for each of the available options so that you can calculate the amount of options selected, and then validate off of that.

Should throw the validation error if more than 3 options are selected, or if 0 options are selected (which would require at least 1).

Depending on your use case, I would consider including ISNEW() or ISCHANGED() functions in the rule as well if it should exclude brand new records, or only apply if that field is modified, etc.

OR(
    IF(INCLUDES(Multiselect_Picklist__c, "Option 1"),1,0) +
    IF(INCLUDES(Multiselect_Picklist__c, "Option 2"),1,0) +
    IF(INCLUDES(Multiselect_Picklist__c, "Option 3"),1,0) +
    IF(INCLUDES(Multiselect_Picklist__c, "Option 4"),1,0) +
    IF(INCLUDES(Multiselect_Picklist__c, "Option 5"),1,0)
    > 3,
    ISBLANK(Multiselect_Picklist__c)
)