Create a new column for missing months with existing data

Hello Anonymus_18 

output : 

steps : 

step  1 : 
adding 2 columns to original table : 

COLUMN1 

Column = 
SELECTCOLUMNS(
OFFSET(
    1, 
    SUMMARIZE(
        date_sol,
        date_sol[date],
        date_sol[value]
    ),
    ORDERBY(date_sol[date], asc)
),
date_sol[value]
)

COLUMN2

next ddate = 
var t = 
SELECTCOLUMNS(
OFFSET(
    1, 
    SUMMARIZE(
        date_sol,
        date_sol[date],
        date_sol[value]
    ),
    ORDERBY(date_sol[date], asc)
),
date_sol[date]
)
return
t

step2 : 

create the table : 

Table_new = 
var datasource = 
FILTER(
SELECTCOLUMNS(
    date_sol,
    "date1",date_sol[date],
    "value", date_sol[value],
    "new_value",date_sol[Column],
    "nextdate", edate(date_sol[next ddate],-1)
),
not isblank([nextdate]) 
)


var added_row = 
DATATABLE(
    "date1" , DATETIME,
    "value", INTEGER,
    "new_value", INTEGER,
    "nextdate", DATETIME,
    {
        {"2021-12-01",0,5, "2022-03-01"}

    }
)


var full_table = 
UNION(
    added_row,
    datasource
)


var res = 
SELECTCOLUMNS(
GENERATE(
    full_table,
    var d1  = [date1]
    var d2 =  [nextdate]
    return
    CALENDAR(d1,d2)
    
    ),

    "newvalue",[new_value],
    "dategenerated",[Date]
)
    
        
       
return 
FILTER(
    res,
    DAY([dategenerated]) = 1
)

you can modify, the code as per your convenience.

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