This can be useful for you: Different Join Functions in Qlikview
In this case you can make a key by yearmonth. Please check first the date format in both of your tables.
You should rename the fields with the same name in the second table in order to avoid to have a synthetic key in your model.
year("DATE") &month("DATE") as %DateKey
"DATE" as "DATE",
month("DATE") as tmonth,
num(month("DATE")) as tmonthnum,
year("DATE") as tyear,
day("DATE") as tday
Left Join (Table1)
tyear&tmonth as %DateKey
tmonth as SchoolDaysTMonth,
tyear as SchoolDaysTYear,
FROM [lib://Data files/RadnorMappingTables.xls]
(biff, embedded labels, table is schooldays$);
Hope it helps!
Also, keep in mind when you are making a key, it always helps to have some kind of delimiter between your key components. Other wise you end up key collisions which will take FOREVER to track down. Below is a simple example
GimmeCollisions: LOAD *, Month & Day AS 'KeyCollision' ; LOAD * Inline [ 'Month', 'Day' 11 , 2 1 , 12 ] ;
The value of KeyCollision in the above table would be '112' for both rows. So I always do something like
Month & '-' & Day AS NoCollision
Month & '/' & Day As NoCollisionsNoSiree