Join Vs Concatenate

[NavinReddy]

Hi All,

When do we prefer join and Concatenate ,

and use could some one help me to know

Thanks In Advance

Niranjan

[Michiel_QV_Fan]

Review the helptext.

Concatenate:

If two tables that are to be concatenated have different sets of Fields, Concatenation of two tables can still be forced with the Concatenate prefix. This statement forces concatenation with an existing named table or the latest previously created Logical Table. A concatenation is in principle the same as the SQL UNION statement, but with two differences: first that Concatenate prefix can be used no matter if the tables have identical field names or not; and secondly that no removal of identical records are made.

Join:

The join prefix joins the loaded table with an existing named table or the last previously created data table. The join is a Natural Join made over all the common Fields. The join prefix may be preceded by one of the prefixes Inner, Outer, Left or Right.

[Anonymous]

Hi Niru,

This Example Will Helpful for you

Concatenate:

Table1:

ID,Name

1,sss

2,aaa

5,bbb

Table2:

ID,Name

6,ccc

3,nnn

7,hhh

Use of Concatenate:

output:

ID,Name

1,sss

2,aaa

5,bbb

6,ccc

3,nnn

7,hhh

Join :

Table1:

ID,Name

1,sss

2,aaa

5,bbb

Table2:

ID,Dept

1,nnn

2,ooo

5,ppp

Use of Join :

Out put:

ID,Name,Dept

1,sss,nnn

2,aaa,ooo

5,bbb,ppp

[NavinReddy]

Thanks for your replays

Could you please explain simple way

Regards

Niranjan

[salto]

Hi,

concatenate: put two tables one below the other. All records from both tables will be on the resultant table.

left Join: very simply, it will "add" fields from table 2 to table 1, on those records that match the coincident fields in both tables.

Hth.

[hic]

See also http://community.qlik.com/blogs/qlikviewdesignblog/2014/01/14/merging-data

HIC

[#7]

Hi Niru,

Concatenate function is meant to add registers to your table.

Join functions are meant to add columns to your table.

That is the eassiest way I found a difference between those functions.

I hope it helps you

[rwunderlich]

See also:

http://qlikviewnotes.blogspot.ca/2009/11/understanding-join-and-concatenate.html

for a walkthrough on how the two differ in data modeling.

-Rob