Morning guys, I am having a issue, I need to make a inner join in soql... Example:

  • Process instance( table1)
  • Process instance step(table 2)

I need to create a table mixing both tables, Id tabel 1 is process instance id in the 2, Table 1 primary key is a forien Key in table 2...

But soql will not support joins for tables I have to write a complete code for this... do you know any other way apart form Apex class?

  • When you mean forieign key do you mean lookups? – Pranay Jaiswal Nov 16 '18 at 10:02
  • Yes @pranay Jaiswal – Monica Henao Nov 16 '18 at 10:18

So Lets Assume this is your Process Table 1

Id(Primary Key),Name,Description__c,Other_Fields__c

And Process Table 2 Schema Looks like this

Id(Primary Key),Name,Process_Table1__c(Lookup / foreign Key to Table 1), Other_Fields__c

Here you can use Join, to get Parent_table1__c Fields querrying the Process_Table2__c, Its called as child-to-parent traversal

SELECT Id,Name,Process_Table1__r.Name,Process_Table1__r.Description FROM Process_Table2__c

Also, Another kind of join is Parent To child, Inner Querry, which allows yoqueryuerry child for a particular parrent

SELECT Id,Name,Description__c,(SELECT Id,Name FROM Process_Table2__r) FROM Parent_table1__c

Src: https://developer.salesforce.com/docs/atlas.en-us.soql_sosl.meta/soql_sosl/sforce_api_calls_soql_relationships_understanding.htm

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  • I tried: 1. SELECT ProcessInstance.*, (SELECT * FROM ProcessInstanceStep) From ProcessInstance; But It will give parsing error – Monica Henao Nov 16 '18 at 22:23
  • 2
    Select * doesn't work in apex, you To specify field names – Pranay Jaiswal Nov 16 '18 at 22:23
  • I put in prosessInstanceId, It says relational objest don't support – Monica Henao Nov 16 '18 at 22:30
  • @MonicaHenao Check out the relationship name. it is possible that you specified the name incorrectly. The relationship name is NOT always __r, and pretty much NEVER __c – zaitsman Oct 3 '19 at 23:59

I would read up on relationships in SOQL because the concept of a JOIN as it works in a regular SQL database doesn't really conform to how SOQL works.

If you want ProcessInstances and their related Steps, you can run a query like this:

    FROM StepsAndWorkitems
    ORDER BY CreatedDate DESC, Id DESC
FROM ProcessInstance

That will retrieve a Process Instance with all of it's "children".

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