# Subtracting one column from another column

**URL:** <https://community.glideapps.com/t/subtracting-one-column-from-another-column/73427>\
**Category:** Ask for Help\
**Created:** [May 16, 2024, 10:15am UTC](https://community.glideapps.com/t/subtracting-one-column-from-another-column/73427 "2024-05-16T10:15:35Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![scotfield123](https://sea2.discourse-cdn.com/flex002/user_avatar/community.glideapps.com/scotfield123/32/62356_2.png) [@scotfield123](https://community.glideapps.com/u/scotfield123)\
**Post date:** [May 16, 2024, 10:15am UTC](https://community.glideapps.com/t/subtracting-one-column-from-another-column/73427/1 "2024-05-16T10:15:35Z")

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| Column 1 | Column 2 | Column 3 |
| --- | --- | --- |
| Email1 | Email2 | |
| Email2 | Email4 | |
| Email3 | | |
| Email4 | | |
| Email5 | | |

Hi guys, it’s an easy one but not for me. How can i populate column 3 with the emails from column 1 that are not present in column 2.  
Kind regards

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**Author:** ![nathanaelb](https://sea2.discourse-cdn.com/flex002/user_avatar/community.glideapps.com/nathanaelb/32/43079_2.png) [@nathanaelb](https://community.glideapps.com/u/nathanaelb)\
**Post date:** [May 16, 2024, 6:13pm UTC](https://community.glideapps.com/t/subtracting-one-column-from-another-column/73427/2 "2024-05-16T18:13:02Z")

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**Answer 1**

- Lookup of column 1 (you get an array)
- If-the-else column: if column 2 is included in lookup then true else ‘null’
- Column 3: Create another If-then-else column. If ITE column (previously) is true then ‘null’ else column 1.

Something like that.

**Answer 2**

Your table does not follow _normal form_, I would redo it.

| Column 1 | Column 2 |
| --- | --- |
| Email 1 | |
| Email 2 | true |
| Email 3 | |
| Email 4 | true |
| Email 5 | |

[![](https://us1.discourse-cdn.com/flex002/uploads/glideapps/original/3X/0/d/0d0e4c5eb656cb7f916d9a438ad13f15c10f45cd.jpeg "Learn Database Normalization - 1NF, 2NF, 3NF, 4NF, 5NF") ](https://www.youtube.com/watch?v=GFQaEYEc8_8)

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**Author:** ![system](https://sea2.discourse-cdn.com/flex002/user_avatar/community.glideapps.com/system/32/53398_2.png) [@system](https://community.glideapps.com/u/system)\
**Post date:** [May 23, 2024, 6:13pm UTC](https://community.glideapps.com/t/subtracting-one-column-from-another-column/73427/3 "2024-05-23T18:13:35Z")

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