Quick Answer: How do you avoid a union in SQL Server?

What can I use instead of a UNION?

There are several alternatives to the union SQL operator:

  • Use UNION ALL.
  • Execute each SQL separately and merge and sort the result sets within your program! …
  • Join the tables. …
  • In versions, 10g and beyond, explore the MODEL clause.
  • Use a scalar subquery.

What can I use instead of UNION all in SQL?

Then the answer is “no”, there isn’t an alternative. UNION and UNION ALL fulfil specific functions. Even functions that fulfil similar roles are often different in some way. For example, ISNULL and COALESCE are often thought to be the very similar (or the same when using 2 parameters), but this really isn’t the case.

How do I create a UNION in SQL without a UNION?

This is possible by using the mutex table as the leftmost table, then LEFT OUTER joining onto the tables which hold the data you really want: select coalesce(c. title, f. title) from mutex left outer join colors as c on i = 0 left outer join flavors as f on i = 1 where i in (0, 1);

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What is opposite of UNION in SQL?

The UNION operator returns all rows. The INTERSECT operator returns all rows that are in both result sets. The EXCEPT operator returns the rows that are only in the first result set but not in the second.

Is Union all slow?

The sql statement is a simple union all between two queries. Each one on its own is instantaneous. Union all them however and it becomes 20x slower.

Can we replace union with join?

UNION and JOIN are totally different things, so cannot replace each other’s functions, but if used as part of a solution to solve a problem, they can contribute in different ways to the same result. In this example, the desired result is to find whether every object is in group A and/or group B.

Does Union in SQL remove duplicates?

The SQL UNION ALL operator does not remove duplicates. If you wish to remove duplicates, try using the UNION operator. … As you can see in this example, the UNION ALL has taken all supplier_id values from both the suppliers table as well as the orders table and returned a combined result set.

What is the difference between UNION and UNION all in SQL Server?

The only difference between Union and Union All is that Union extracts the rows that are being specified in the query while Union All extracts all the rows including the duplicates (repeated values) from both the queries.

Which is faster UNION or UNION all?

UNION ALL is faster and more optimized than UNION. But we cannot use it in all scenarios. UNION ALL with SELECT DISTINCT is not equivalent to UNION.

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How many UNIONs can you have in SQL?

I tested it for 8,192 UNIONs with SQL Server 2008 Enterprise. It executed OK. In SQL Server 2000, the max is something like 254

What does UNION all do in SQL?

The UNION ALL command combines the result set of two or more SELECT statements (allows duplicate values).

What is the difference between UNION and join in SQL?

UNION in SQL is used to combine the result-set of two or more SELECT statements. The data combined using UNION statement is into results into new distinct rows. JOIN combines data from many tables based on a matched condition between them. … It combines data into new columns.

How do you do not in SQL?

Overview. The SQL Server NOT IN operator is used to replace a group of arguments using the <> (or !=) operator that are combined with an AND. It can make code easier to read and understand for SELECT, UPDATE or DELETE SQL commands.

What is difference between intersect and inner join?

They are very different, even in your case. The INNER JOIN will return duplicates, if id is duplicated in either table. INTERSECT removes duplicates. The INNER JOIN will never return NULL , but INTERSECT will return NULL .

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