Cross Join is not the same as ,

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Script Name Cross Join is not the same as ,
Description Oracle SQL allows tables to be joined using a combination of the old comma-separated (,) syntax along with the newer ANSI joins (such as CROSS JOIN). In some ways, the "," operator can be considered as a variation on a CROSS JOIN; however, the Oracle SQL syntax does not treat these exactly the same. Instead, the "," operator separates the FROM clause into separate parts, and each ON clause can only see columns from the tables involved in its part.
Area SQL General / SQL Query
Contributor Jeffrey Kemp
Created Wednesday November 22, 2017

Statement 1

create table t1 (id number)

Table created.

Statement 2

create table t2 (id number)

Table created.

Statement 3

create table t3 (id number)

Table created.

Statement 5

This form works because the two joins form part of the same join clause.

works

select * 
from   t1 
cross join t2 
join t3 
  on t3.id = t2.id and t3.id = t1.id

no data found

Additional Information