TABLE POOL IN ABAP

What is a table pool?

A table pool (or pool) is used to combine several logical tables in the ABAP/4 Dictionary. The definition of a pool consists of at

least two key fields and a long argument field (VARDATA).

Abap 4 query doesn't allow to use pool / cluster tables in a table join . is there any work-around for this ? How can the data in pool cluster tables be extracted without writing abap code

A table pool or table cluster should be used exclusively for
storing internal control information (screen sequences, 
h as documentation). Data of commercial relevance is usually
program parameters, temporary data, continuous texts su
c stored in transparent tables.  A table in the database in which all records from the pooled 
tables assigned to the table pool are stored corresponds to 
a table pool. 

Table Clusters
============== 
 Several logic
al data records from different cluster tables
can be stored together in one physical record in a table
cluster.  
key consists of a series of freely definable key fields an
A cluster
d a field (Pageno) for distinguishing continuation 
ta) that contains the contents of the data fields of the clu
records. A cluster also contains a long field (Vard
aster tables for this key. If the data does not fit into the long 
field, continuation records are created.

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