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The MID Function in Tableau.

This one caught me out in a certification exam, so I made a video about MID before I could forget it again.

Tim Ngwena •8 June 2021 •1 min read •7 min watch •2.6K

Part ofTableau Functions

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MID() returns characters from a string starting at a specified position, with an optional second argument controlling how many characters to return
Choosing position 2 effectively drops the first character; the start position is treated as character one for the length count
For neatly structured data, LEFT or RIGHT functions are usually simpler than MID
Wrapping FIND() inside MID() lets you dynamically locate a character, such as finding the position of an @ sign
Adding +1 to a FIND() result lets you start MID one character past the matched character, useful for extracting an email domain

0:00Hey, it's Tim here. In today's video, we're

0:01going to be looking at a function called

0:02mid. Now this

0:03this one actually caught me out in a

0:05certification exam. It came up in the

0:07partner consultant exam

0:08that you have to do if you're a tableau

0:10partner and it's just one of those

0:11functions where I've

0:12never had to use it so I just had no clue

0:15what it did so I guessed I didn't get the

0:17question right

0:18unfortunately but nonetheless I didn't stop

0:20the certification so what I wanted to do is

0:22immediately

0:22make a video about it because if it's

0:24something that I don't know then hopefully

0:25it's going to

0:26be useful for everyone. So I'm just going

0:28to connect to Superstore sales here and we

0:30're just

0:30going to get stuck in. The first thing I'm

0:32going to do is I'm actually going to bring

0:33in some

0:33subcategories okay so subcategories tend to

0:36be good because they're nice and small and

0:38we can

0:38kind of see the structure it's not a long

0:40list as well and I'll just to just to make

0:43this table make

0:44more sense I'll bring in sales and we'll

0:46keep it at that. I'll go to format font and

0:48I will also

0:49change the size of this text so it's easier

0:51to see so it's much much easier for

0:52everyone to see.

0:53Okay so now that we've done that we can get

0:56stuck into the mid function so let's go

0:58ahead and close

0:59a formatting tab and create a calculated

1:01field and I'll put this window to the right

1:04hand side here so

1:04all I need to do is type in mid and you can

1:07see the function comes up now if you've

1:09never used this

1:10function I want to hear from you in the

1:11comments below because I also think this is

1:13harsh of

1:14Tableau to put this in the exam because who

1:16on earth has ever used this function and

1:18actually

1:18when you go through the use case I just I

1:21've just never found a need for this

1:23normally if you're

1:24doing this kind of thing you might use

1:26something a little bit more structured like

1:28regex to kind

1:29of extract what you need but now

1:30nevertheless let's go ahead and look at the

1:33mid function so

1:34just over here on the right hand side you

1:36see you get a very lengthy description of

1:38what it does

1:39essentially it allows you to return text

1:41starting from a specified position in the

1:44string and then

1:45you've got an optional second argument

1:46which tells you how many characters it

1:48should stop after okay

1:50so let me just break that down into sort of

1:52plain English I don't know why it's called

1:54mid I think

1:55this is maybe database terminology right so

1:57we're going to call this on the subcategory

1:59field so

2:00that's all good we're going to hit a comma

2:02and then we're just going to say two okay

2:04we're just

2:04going to choose an arbitrary number just to

2:06make that work and we just call this subcat

2:09mid two

2:10okay and once we do that we hit apply and I

2:12'm just going to bring it into the field

2:14right next

2:15to subcategories subcategory so you can see

2:17what it's doing so now let's drop that in

2:20and you can

2:20see that essentially if I just sort of

2:23decipher this and it's basically taking a

2:25subcategory

2:26field okay and essentially it's going to

2:29get to the second position in this string

2:32so if I take

2:33my little subcategory string and I go here

2:36to accessories you'll see that it goes to

2:38the second

2:39position so the first one is a the second

2:41is c and then from c it returns the rest of

2:44the string

2:45that's all it's doing so in pretty much all

2:47of these all I've done by selecting two is

2:49I've

2:50emitted the first letter okay let's clear

2:52that and let's change this to four so you

2:54can see that

2:55working across all of them hit apply and

2:57now you can see that it goes to the fourth

2:59one so let's

3:00see here appliances you have a one two

3:02three and then at l you have the fourth one

3:05so that's where

3:06it starts that's what it perceives as the

3:08first letter in the word or whatever

3:10character and then

3:11it starts alliances over there now there's

3:14an optional second argument which is if I

3:16hit a

3:17comma and then I say two it's basically

3:19going to tell it once you get to that

3:21fourth position

3:22return me just two characters essentially

3:24you're specifying the length of what it

3:26should return

3:26so now if I hit apply you'll see that I

3:29just get two characters because essentially

3:31it's finding

3:31the fourth position it's treating that as

3:34number one and then it's returning two

3:36characters after

3:37that so one and two and that's what you get

3:40okay so it's kind of a weird function I

3:43just I can't

3:43think of a use case where this is this is

3:46going to be what I'm doing because if you

3:48're specifying

3:49this sort of structure then you probably

3:51have some pretty structured data so you

3:53might as well just

3:54go and do like a left or a right function

3:56right and return various things you might

3:59also as for

4:00example specify in another way it's more

4:02common that you you typically need to

4:04dynamically

4:05specify where to start and finish and so

4:07maybe that is the use case because what you

4:10could do

4:10is where it says four is you could replace

4:12this four with another function that looks

4:15for the

4:15position of a specific character okay so if

4:17you may be looking for I don't know an out

4:20sign you

4:20could maybe get this mid function to return

4:23everything after the out sign up to an

4:26unlimited

4:27number of characters right in an email

4:29address so maybe that's I've really sort of

4:31built a far

4:32fetched use case there and tablet will

4:33automatically split that email address so

4:36you don't need to use

4:37that function to do that but if you had to

4:38that's sort of like a brute force way of

4:40doing that okay

4:41so just to give you an example let's let's

4:43go ahead and actually do that example I'll

4:45create

4:46like an arbitrary field and I'll just call

4:48uh [email protected] so let's say I

4:56wanted to

4:57return everything after the outside because

4:59I wanted just the domain let's go ahead and

5:02just

5:02show you how that looks like so let's just

5:04say john.smith uh enter we'll call this our

5:07field

5:07our field test and hit apply okay and if I

5:11bring that in you see it applies to every

5:14single row so

5:15now we can see that's that nice and working

5:17so now we can go ahead and use that in our

5:20field so let's

5:20go ahead and use the mid function let's

5:22make this a lot bigger and we're just going

5:24to bring in field

5:26test okay and what I'd like to do is find

5:28the position of the at sign so in order to

5:31do that

5:31if you do the find function you'll see find

5:35will return the position of a particular

5:37thing so what

5:38I'm going to do is on a new line I'm just

5:40going to type the find function okay and I

5:42'm going to bring

5:43in the thing I'm looking for which is the

5:46field test and the thing in the field test

5:50that I'm

5:51looking for is the at at sign so let's do

5:54an at where's my at sign here so find will

5:58go find the

5:58position of the uh at sign so I'm going to

6:01grab that and I'm going to put that in here

6:03inside of

6:04the mid so what this mid will do is it will

6:06use the position of the at sign to choose

6:08where to start

6:09and what I would like to do is I will put

6:12that find uh in its own uh bracket so that

6:18I can add

6:18plus one because I don't want the position

6:21of that uh find the at sign I want the

6:23position of the next

6:24character so if I add a plus one to that

6:26that all makes sense so this should leave

6:28me with the url

6:30of the email I'm fairly certain when you

6:32automatically pass things out in Tableau

6:34this

6:34is what it's doing so let's go ahead and

6:37drop that in there and boom you just get

6:39the url so

6:40um I've sort of really gone out of my way

6:43to sort of show this uh working maybe that

6:45's a way maybe

6:46that's a useful thing you might be able to

6:48use maybe you have some semi-structured

6:50data you can't

6:50be bothered with regex and the mid function

6:52is going to be a nice little use case for

6:54you

6:54but hopefully that's helped you and uh it's

6:56helped me reinforce what the mid function

6:58is at least in

6:59my own mind the next time it comes in a

7:01certification exam you don't have to worry

7:03about it okay thanks

7:04for watching if you've enjoyed this video

7:06you know what to do hit subscribe like

7:08share this video

7:09with other people who might like it and be

7:10sure to check out TableauTim.com where I

7:12have all the

7:13same videos but in a nicer more browsable

7:15format and of course check out the social

7:17media channels

7:17as well TableauTim pretty much anywhere and

7:19also the discord channel which is going to

7:22be in the

7:22link below all right get stuck in and I'll

7:24catch you in the next one

Rollup

MID() returns part of a string starting at a chosen position, with an optional length argument controlling how many characters come back. It's a fiddly, rarely-needed function on its own, but combined with FIND() it becomes a genuinely useful way to extract dynamic substrings like an email domain.

Demonstrated on Superstore subcategory names, then on a made-up email address field to build a more realistic example.

The Breakdown

Basic MID syntax 0:54

MID(string, position) returns everything in the string from that position onwards, counting the start position as character one. Choosing position 2, for example, effectively drops just the first character.
See it in practice on real values 2:20

Drop the calculated field next to the source field to watch how the start position lines up character-by-character across every row — a good way to sanity-check what MID is actually doing before relying on it.
Add the optional length argument 3:14

A second argument, MID(string, position, length), tells it how many characters to return after the start position, again counting that position as one. Without it, MID returns everything to the end of the string.
When MID isn't the right tool 3:40

For neatly structured, fixed-format data, LEFT or RIGHT are usually simpler and clearer than MID — reach for MID only when the position you need isn't fixed.
Make the position dynamic with FIND 4:01

Instead of hardcoding a start position, nest FIND() inside MID() to locate a specific character, such as an @ sign, so the extraction works even when its position varies row to row.
Build the email-domain extraction 5:20

Wrap FIND(field, "@") inside MID() as the position argument, then add +1 to that FIND result so extraction starts one character after the @ rather than on it. This must be done in this order — find the marker character first, offset it, then feed that into MID — and it leaves you with just the domain.

Worth Knowing

The start position argument is treated as character one for length-counting purposes, which can be confusing when combining it with FIND offsets.
Tableau's automatic field-splitting likely does something similar to this FIND+MID combination internally, so you don't need it for simple cases.
This is a brute-force approach — for genuinely messy or variable text, regex functions are usually a cleaner alternative.

Use It When

Reach for MID with FIND when you have semi-structured text data (like email addresses) and need to dynamically extract a substring whose position varies, but you'd rather avoid regex.

How this Rollup was made provenance & method

A Rollup is drafted by AI from the video's transcript, then reviewed and edited by Tim. Everything used to produce this one is listed below — the model, the exact prompt, and the source video — so the process is transparent and reproducible.

Transcription: On-device — NVIDIA Parakeet v3 for recent videos, OpenAI Whisper large-v3 for earlier ones. The transcript never leaves the machine or gets published.
Drafting: Claude Sonnet 5 in the cloud, from that transcript.
Prompt: The exact Rollup prompt (v2) — the full system prompt, unedited.
Source video: Watch on YouTube
Drafted: 5 July 2026 at 09:38
Reviewed & edited: 5 July 2026 at 09:41 · by Tim Ngwena

Model + prompt + video is everything you'd need to recreate a Rollup like this yourself. The one thing we don't share is the transcript.

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