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sqlsybase

how to have hardcoded blank value of integer data type union with integer datatype column

select id , '' as employee_id from table1
union
select id , emp_id as employee_id from table2

but i am getting error that incompatible datatype of employee_id from two joining union queries. so how to solve this issue.

emp_id is numeric datatype

Solution

  • If you want strings, then convert to strings:

    select id , cast('' as varchar(255)) as employee_id from table1
union all
select id , cast(emp_id as varchar(255) as employee_id from table2;

    Normally, you would use NULL rather than '', which is more compatible with more types:

    select id , NULL as employee_id from table1
union all
select id , emp_id as employee_id from table2;

    Note that I changed the union to union all. union incurs overhead for removing duplicates. Only use it if you want to incur that overhead.