QUESTION :
How do you join two datasets in excel from time-series, but the observations have been made at different times. How would you combine the observations in one table with the second?
Example:
table 1:
+---------+-------+
| date | price |
+---------+-------+
| 1/14/96 | 1.95 |
+---------+-------+
| 1/19/96 | 1.97 |
+---------+-------+
| 1/22/96 | 2.01 |
+---------+-------+
table 2:
+---------+--------+
| date | demand |
+---------+--------+
| 1/10/96 | 400 |
+---------+--------+
| 1/19/96 | 300 |
+---------+--------+
| 1/25/96 | 200 |
+---------+--------+
So that the desired result is either this:
table 3:
+---------+-------+--------+
| date | price | demand |
+---------+-------+--------+
| 1/10/96 | | 400 |
+---------+-------+--------+
| 1/14/96 | 1.95 | |
+---------+-------+--------+
| 1/19/96 | 1.97 | 300 |
+---------+-------+--------+
| 1/22/96 | 2.01 | |
+---------+-------+--------+
| 1/25/96 | | 200 |
+---------+-------+--------+
Or this:
table 4:
+---------+-------+--------+
| date | price | demand |
+---------+-------+--------+
| 1/19/96 | 1.97 | 300 |
+---------+-------+--------+
ANSWER :
There are several ways you could do this. How messy a job it is depends on whether or not you have duplicate dates in your table or common dates between them. My first thought is an INDEX/MATCH approach. Here’s what I would do if I were trying to do it with your example tables:
- Put table 1 in sheet 1, starting at cell A1, and table 2 in sheet 2, starting again at cell A1.
- Create the column headers for table 3 in sheet 3.
- Copy the dates from table 1 into table 3. Then copy the dates from table 2 to the bottom of the list you put in table 3. Now you have the dates from both in one column.
Now, in table 3: -
In the price column, use a formula along the lines of
=INDEX(Sheet1!$B$2:$B$4,MATCH(Sheet3!A2,Sheet1!$A$2:$A$4,0))
This pulls the price from the corresponding value in sheet 1.
-
In the demand column, use a formula along the lines of
=INDEX(Sheet2!$B$2:$B$4,MATCH(Sheet3!A2,Sheet2!$A$2:$A$4,0))
This pulls the demand from the corresponding value in sheet 2.
What you’ll get is a table that looks like your Table 3, but with some duplicate rows. You can use the Data – Data Tools – Remove Duplicates feature to clean it up.
This may not be a perfect fit for your issue, but hopefully it’s a starting point.