Welcome to the Airtable community!
I like using a multi-line syntax with nested IF
s.
IF(
{PROJECT APPROACH} = "LEAD",
DATEADD({DELIVERY DATE}, -15, 'weeks'),
IF(
{PROJECT APPROACH} = "PARTNER",
DATEADD({DELIVERY DATE}, -14, 'weeks'),
IF(
{PROJECT APPROACH} = "ADVISE",
DATEADD({DELIVERY DATE}, -13, 'weeks')
)))
You can also consider using a SWITCH
instead of nested IF
s.
SWITCH( {PROJECT APPROACH},
"LEAD", DATEADD({DELIVERY DATE}, -15, 'weeks'),
"PARTNER", DATEADD({DELIVERY DATE}, -14, 'weeks'),
"ADVISE", DATEADD({DELIVERY DATE}, -13, 'weeks')
)
I also sometimes invert the order of the functions to reduce repetition.
DATEADD(
{DELIVERY DATE},
SWITCH( {PROJECT APPROACH},
"LEAD", -15,
"PARTNER", -14,
"ADVISE", -13
),
'weeks'
)