What is the syntax of union in SQL?
The basic syntax of a UNION clause is as follows − SELECT column1 [, column2 ] FROM table1 [, table2 ] [WHERE condition] UNION SELECT column1 [, column2 ] FROM table1 [, table2 ] [WHERE condition]
What is UNION in DB2?
The UNION in DB2 is used to merge two or more SELECT statements. The SELECT statements can be on a single table or on multiple tables. Each SELECT statement is processed individually and their results are combined to give us the final result rows.
What is difference between UNION and JOIN in DB2?
JOIN. The join clause combines columns from two or more tables while the UNION operator combines rows from two or more subselects. In other words, join appends the result sets from tables horizontally while UNION appends result sets from subselects vertically.
How do you UNION a query?
In this step, you create the union query by copying and pasting the SQL statements.
- On the Create tab, in the Queries group, click Query Design.
- On the Design tab, in the Query group, click Union.
- Click the tab for the first select query that you want to combine in the union query.
What is union in SQL with example?
The Union operator combines the results of two or more queries into a single result set that includes all the rows that belong to all queries in the Union. In simple terms, it combines the two or more row sets and keeps duplicates. For example, the table ‘A’ has 1,2, and 3 and the table ‘B’ has 3,4,5.
How do you union a column in SQL?
The UNION operator is used to combine the result-set of two or more SELECT statements.
- Every SELECT statement within UNION must have the same number of columns.
- The columns must also have similar data types.
- The columns in every SELECT statement must also be in the same order.
Is full join same as UNION?
They’re completely different things. A join allows you to relate similar data in different tables. A union returns the results of two different queries as a single recordset.
Why do we use UNION in SQL?
The SQL UNION operator is used to combine the result sets of 2 or more SELECT statements. It removes duplicate rows between the various SELECT statements. Each SELECT statement within the UNION must have the same number of fields in the result sets with similar data types.