topic Re: Joining Tables with Blank Values in QlikView

Joining Tables with Blank Values

Wed, 19 Apr 2017 20:03:09 GMT

Hello Qlik Community,

I would like to join Status in Table 2 to Table 1 based on the criteria in Table 2 where not blank.

If I use a left join Table 2 Code, Type, Model; status is only added to ID's 3 and 5.

If I use a left join Table 2 Code, Type; status is added to ID's 2, 3, 5, 7,9 (good) as well as ID 6 (bad).

Additionally ID's 3 and 5 just happen to have the same status. I would expect issues if they were different.

Sorry for the poor synatx/short-hand. I hope I conveyed what I'm trying to accomplish.

Thanks for your help. Shaun.

Table1:

ID	Code	Type	Model
1	Arthur	Tangerine	9
2	Arthur	Carrot
3	Walter	Tangerine	9
4	Walter	Carrot
5	Walter	Tangerine	6
6	Walter	Tangerine	8
7	Corrina	Sprite	4
8	Corrina	Tangerine	9
9	Corrina	Sprite

Table2:

Code	Type	Model	Status
Arthur	Carrot		Open
Walter	Tangerine	9	Closed
Walter	Tangerine	6	Closed
Corrina	Sprite		Open

Status of all others should be 'Pending', but I can live with a blank

Combined Table should look like:

ID	Code	Type	Model	Status
1	Arthur	Tangerine	9	Pending
2	Arthur	Carrot		Open
3	Walter	Tangerine	9	Closed
4	Walter	Carrot		Pending
5	Walter	Tangerine	6	Closed
6	Walter	Tangerine	8	Pending
7	Corrina	Sprite	4	Open
8	Corrina	Tangerine	9	Pending
9	Corrina	Sprite		Open

Re: Joining Tables with Blank Values

hector_munoz — Wed, 19 Apr 2017 20:13:34 GMT

Hi Shaun,

Try the following:

MAP_STATUS:

MAPPING LOAD Code & '|' & Type & '|' & Model AS MAP_KEY

Status AS MAP_DESC

RESIDENT TABLE2;

TABLE1:

LOAD .....

.....

ApplyMap('MAP_STATUS', Code & '|' & Type & '|' & Model, 'Pending') AS Status

FROM xxxxx;

Regards,

Re: Joining Tables with Blank Values

Wed, 19 Apr 2017 23:55:26 GMT

Thanks Héctor. That did it.

Re: Joining Tables with Blank Values

Thu, 20 Apr 2017 15:54:00 GMT

New question. How can I use a wildmatch where blanks exist in Table2 (or should I be using something else)?

Basically, Table2 contains a blank, I don't care what that value is in Table1. I want Status based on only populated fields in Table2

For example, if ID 7 in Table1 has a Model = 4 whereas ID 9 has no Model, the Status in the resulting table would have ID 7 as Pending, but ID 9 as Open.

Re: Joining Tables with Blank Values

hector_munoz — Thu, 20 Apr 2017 20:02:11 GMT

Hi Shaun,

Then, if I donot miss anything, you should use an IF statement like:

If(Len(Model) = 0,

'Pending',

ApplyMap('MAP_STATUS', Code & '|' & Type & '|' & Model, 'Pending')) AS Status

, here if a record has Model without information you always put "Pending" literal; in other case you use tha ApplyMap() function.

Hope it serves!

Regards,

Re: Joining Tables with Blank Values

annapochyla — Thu, 20 Apr 2017 20:09:37 GMT

You could try using second applymap function, that will ignore Model value from table1.

ApplyMap('MAP_STATUS', Code & '|' & Type & '|' & Model, ApplyMap('MAP_STATUS', Code & '|' & Type & '|', 'Pending') ) AS Status

Re: Joining Tables with Blank Values

Fri, 21 Apr 2017 14:30:44 GMT

Thanks for the suggestions guys.

Héctor,

Your first reply was spot on for that question. So thanks for that help. I understand where you are going with your reply to my second question. However, if any field is blank in Table2, that means I don't care what the corresponding value in Table1 is. I can be any value or even blank. I hope that helps clarify what I'm trying to achieve.

Anna,

Thanks for your reply. I think you understand what I'm trying to accomplish in my second question. I expect your solution will work in this situation. However, I anticipate in the future I will need to add more fields to Table1 and Table2. If I need to add 10 more fields, I would need to have multiple nested ApplyMap statements for every combination. I feel that there must be a more elegant solution to allow for expansion of the number of fields without, having an exponential grow in the size of my nested statements. Let me know if that doesn't make sense.

Thanks to both of you for your help, time and patience. Shaun.

Re: Joining Tables with Blank Values

hector_munoz — Fri, 21 Apr 2017 15:24:30 GMT

Hi Shaun,

If I have understood it well you only want those records coming from TABLE2 where they have not any empty or null value, have you? Then you could create MAP_STATUS table with a WHERE condition like below:

MAP_STATUS:

MAPPING LOAD Code & '|' & Type & '|' & Model AS MAP_KEY

Status AS MAP_DESC

RESIDENT TABLE2

WHERE SubStringCount('|' & Code & '|' & Type & '|' & Model & '|', '||') = 0;

With this condition: SubStringCount('|' & Code & '|' & Type & '|' & Model & '|', '||') = 0 we will not take into account those records with two pipes in a row; and 2 pipes in a row using a pipe as a separator of key fields mean that any of the key fields is empty or null. I donot know if I can explain it propoerly...

Hope it serves!!!

Regards,
H

Re: Joining Tables with Blank Values

Fri, 21 Apr 2017 18:59:47 GMT

Thanks Héctor. I think your code will exclude any rows from Table2 from the Map. That means that ID in the Combined table will be mapped as Pending. I want to map based on any fields that are populated in Table2. If the field is not populated in Table2, I still want to map to Table1 but based only the remaining fields.

If I could Map Table 2 with a wildcard like * instead of null(), but I don't think we can map wildcards, correct?

I update the Tables in the origianl post to add a Model to ID 7. There will likely be more Fields added in the future, but for the items already mapped in Table2, those additional fields would also be mapped as * to not effect the prior results.

I don't think I'm explainnig this very well. Sorry.

Re: Joining Tables with Blank Values

Kushal_Chawda — Sat, 22 Apr 2017 06:43:52 GMT

see this

Table2:

mapping LOAD trim(Code)&trim(Type) as Model ,

Status

FROM

[https://community.qlik.com/thread/257637]

(html, codepage is 1252, embedded labels, table is @2)

where len(trim(Model))=0;

Table2_1:

mapping LOAD trim(Code)&trim(Type)&trim(Model) as Model ,

Status

FROM

[https://community.qlik.com/thread/257637]

(html, codepage is 1252, embedded labels, table is @2)

where len(trim(Model))>0;

Table1:

LOAD *,

if(Status1='Pending' and Status2<>'Pending' ,Status2,

if(Status1<>'Pending' and Status2='Pending' ,Status1,Status2)) as Status;

LOAD ID,

Code,

Type,

Model,

applymap('Table2',trim(Code)&trim(Type),'Pending') as Status1,

applymap('Table2_1',trim(Code)&trim(Type)&trim(Model),'Pending') as Status2

FROM

[https://community.qlik.com/thread/257637]

(html, codepage is 1252, embedded labels, table is @1);

Re: Joining Tables with Blank Values

Sun, 23 Apr 2017 19:49:08 GMT

Thanks Kushal Chawda. That works. In a case where I 'filter' based on perhaps only one field, I would think I would have to created additional variants of your mapping load and applymap, correct? For example, if Table1 and Table2 were shown as shown below, to create the combined table your script would also add the following.

This seems lik the script could quickly grow larger as the number of fields in Table2 increases. If I had 10,000 IDs and 8 fields in Table2 that may or may not be blank, I would need to add a new mapping Load, apply map and if statements for each cobination of those 8 fields, correct?

One more question, is there a particular reason you used trim? Is that a best practice or something else? Just curious.

Thanks again. Shaun.

Table2:

...

Table2_1:

...

Table2_2:

mapping LOAD trim(Code) as Model ,

Status

FROM...

where len(trim(Model))=0 and len(trim(Type))=0;

Table1:

LOAD *,

if(Status3<>'Pending',Status3,

if(Status1='Pending' and Status2<>'Pending' ,Status2,

if(Status1<>'Pending' and Status2='Pending' ,Status1,Status2))) as Status;

LOAD ID,

Code,

Type,

Model,

applymap('Table2',trim(Code)&trim(Type),'Pending') as Status1,

applymap('Table2_1',trim(Code)&trim(Type)&trim(Model),'Pending') as Status2

applymap('Table2_2',trim(Code),'Pending') as Status3

FROM

Table1:

ID	Code	Type	Model
1	Arthur	Tangerine	9
2	Arthur	Carrot
3	Walter	Tangerine	9
4	Walter	Carrot
5	Walter	Tangerine	6
6	Walter	Tangerine	8
7	Corrina	Sprite	4
8	Corrina	Tangerine	9
9	Corrina	Sprite
10	Victor	Carrot
11	Victor	Tangerine	8
12	Victor	Sprite	4
13	Victor	Sprite

Table2:

Code	Type	Model	Status
Arthur	Carrot		Open
Walter	Tangerine	9	Closed
Walter	Tangerine	6	Closed
Corrina	Sprite		Open
Victor			Closed

Combined Table:

ID	Code	Type	Model	Status
1	Arthur	Tangerine	9	Pending
2	Arthur	Carrot		Open
3	Walter	Tangerine	9	Closed
4	Walter	Carrot		Pending
5	Walter	Tangerine	6	Closed
6	Walter	Tangerine	8	Pending
7	Corrina	Sprite	4	Open
8	Corrina	Tangerine	9	Pending
9	Corrina	Sprite		Open
10	Victor	Carrot		Closed
11	Victor	Tangerine	8	Closed
12	Victor	Sprite	4	Closed
13	Victor	Sprite		Closed

Re: Joining Tables with Blank Values

Kushal_Chawda — Mon, 24 Apr 2017 05:44:40 GMT

Number of IDs would not make a difference until you have very large data set. Also in your case, there will be a fix key like code, model and type based on which you would do the mapping so number of fields also doesn't matter.

Re: Joining Tables with Blank Values

Mon, 24 Apr 2017 11:43:28 GMT

Thanks Kushal Chawda. It is clear that number of IDs doesn't matter.I only mention that because as the number of IDs increases, the number of fields I will want to sort by will also increase. Table2 (where I'm pulling my Status map) could easily end up having 200+ rows with 20 different fields to sort on. Each row will have a different mixture of sorting fields.

For the example with the current fields, the script only requires the following field combinations for 1) Map Loading, 2)nested if statements and 3) apply map:

-Code where Type & Model are null

-Code & Type where Model is null

-Code, Type & Model where none are null

The number of possible combinations will at a minumum be squared, then multiply that again for each variant within each field. I'm not saying this is the case, but it could grow there.

If I add more fields and combinations it can easily exapnd to:

-Code where (Type, Model, Color, Size, Brand, Location, Season) are null()

-Code & Type where (Model, Color, Size, Brand, Location, Season) are null()

-Code, & Model where (Type, Color, Size, Brand, Location, Season) are null()

-Code & Color where (Type, Model, Size, Brand, Location, Season) are null()

-Code, Brand, & Location where (Type, Model, Color, Size, Season) are null()

-Code, Model, & Season where (Type, Color, Size, Brand, Location) are null()

-Code, Size where (Type, Model, Color, Size, Brand, Location, Season) are null()

-Code, Brand, & Size where (Type, Model, Color, Location, Season) are null()

-Code, Color, Location where (Type, Model, Size, Brand, Season) are null()

-Code, Type, Model & Season where (Color, Size, Brand, Location) are null()

...

In that case, I would have to have 10 Map load scripts, 10 nested if statements, 10 applymap functions.

For each addition field combination added to Table2, I would need to revise the script and add that new field combination to the script.

Perhaps this is turning in to a string issue instead? I'm just throwing ideas out there. Thanks again for your help. Shaun