y join keep concatenate

[#1]

Why join and why Keep and when we should use concatenate in projects Adv and disadvantages in qlikview

[its_anandrjs]

1. Join is used when you want to combine two tables into one on the basis of the unique master keys or ID in the tables, but not necessary both tables have unique keys but practice is one master table is used for join.

2. Keep is also used with join but in this case the another table is available independently in the data model.

3. Concatenate is used when there is two or more table has same field names and they are same to each other or may be different number of rows in the tables, but they are exactly the same but always here also not necessary they have same fields. But if using the concatenate in between them will increase the number of the rows after the concatenation and this is disadvantage for the large amount of data because it takes lot of time to load in the model. The best advantage in concatenate is to connect this other table into single table with effectively less time to load in data model.

Regards,

Anand

[SunilChauhan]

Join: is used  based on key values and matching Records in two table

keep : also based on key values and matching records.keep will have two table instead.but tables are reduced based on keep type for example Left keep second table reduced based on first table and records not matching with first table

removed after left keep

Concatenate :appent the row to first table from  sceond table  

example

tab1: 

Empid,Sales

1,100

2,300

3,400

tab2: 

Empid,dept

2,10

3,20

5,40

Result:

after Left Join:

Empid,Sales,dept

1,100,

2,300,10

3,400,20

after left keep

Empid,Sales,dept

1,100,

2,300,10

3,400,20

and tables have data like

tab1: 

Empid,Sales

1,100

2,300

3,400

tab2: 

Empid,dept

2,10

3,20

after Concatete

tab1: 

Empid,Sales

1,100

2,300

3,400

2,   ,10

3 , , 20

hope this helps

[ashfaq_haseeb]

Hi,

For better understanding, have a look at below posts.

http://community.qlik.com/docs/DOC-6562

http://community.qlik.com/thread/39177

http://community.qlik.com/thread/134760

Regards

ASHFAQ