SQLite Union Operator
SQLite UNION Operator is used to combine the result set of two or more tables using SELECT statement. The UNION operator shows only the unique rows and removes duplicate rows.
While using UNION operator, each SELECT statement must have the same number of fields in the result set.
We have two tables "STUDENT" and "DEPARTMENT".
The "STUDENT" table is having the following data:
The "DEPARTMENT" table is having the following data:
Example1: Return Single Field
This simple example returns only one field from multiple SELECT statements where the both fields have same data type.
Let's take the above two tables "STUDENT" and "DEPARTMENT" and select id from both table to make UNION.
Example2: Union with Inner and Outer Join
Let's take the above two tables "STUDENT" and "DEPARTMENT" and make an inner join and outer join according to the below conditions along with UNION Clause: