I'm interested to have a table that cointains all variable (a,x,y,z...) in a specific dates range ( example from 01/01/2020 to 31/01/2020).
The problem is that merging Tab 1 and Tab 2 I obtain also the variable like "a" (in my example) which have missing value for ALL days in 2020,
Does it possible delete a column without specify the name of Variable "a" but delete under conditions?
I mean, if in tab3 there are variables that have "." for ALL days into 2020, which is the method to delete they?
Consider that my Tab3 is built by 250 variable, so specify conditon for each of them it is quite time expensive and furtheremore if the number of variable increase I should add it in my query.
Thank you for your help