Sql union all syntax error

ProgrammerAH

Programmer Guide, Tips and Tutorial

SQL Union, union all usage and common errors and Solutions

The SQL UNION operator
The UNION operator is used to combine the result sets of two or more SELECT statements.
Note that the SELECT statement within the UNION must have the same number of columns. Columns must also have similar data types. Also, the order of the columns in each SELECT statement must be the same.
The UNION SQL grammar

Note: By default, the UNION operator picks a different value. If duplicate values are allowed, use UNION ALL.
SQL UNION ALL syntax

Also, the column name in the UNION result set is always equal to the column name in the first SELECT statement in the UNION.
Error reporting and resolution
When using the UNION operator, the following error can easily be reported:
Parse error: org. Apache. Hadoop. Hive. Ql. Parse. ParseException: line 5-0 always recognize input near “and” (” and “the UNION, ‘ ‘SELECT’ set in the operator
Simplify the code used as follows:

This is mainly because the UNION operator can only join fields to fields, but not fields to tables or tables, even if the number of fields and their names and formats are the same.
Therefore, you can’t have parentheses around the UNION operator, because it’s easy for SQL to determine that this is a subquery/table and therefore to report an error when joining
The solution


    > SELECT FROM TABLE D > SELECT FROM TABLE D > SELECT FROM TABLE D > SELECT FROM TABLE D > SELECT FROM TABLE D > SELECT FROM TABLE D > SELECT FROM TABLE D > SELECT FROM TABLE D > SELECT FROM TABLE D > SELECT FROM TABLE D > SELECT FROM TABLE D > SELECT FROM TABLE D
    Matters needing attention

Источник

SQL Server Portal

Real world SQL scenarios & its unique & optimized solutions

SQL SERVER – Fix – Error :156 – Incorrect syntax near the keyword ‘UNION’.

UNION operator is one of the most frequent operators used in SQL Server scripting. As per MSDN it is used to combine 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 . But there is an issue with Union operator which prohibits order by for each table separately while using UNION / UNION ALL. It generates an error.

Let me explain this error in detail :

Message Number: 156

Severity : 15

Error Message: Incorrect syntax near the keyword ‘UNION’.

Let me create a sample to demonstrate this error.

Once you created the above sample, lets make a UNION ALL query and try to ORDER BY each table separately.

Msg 156, Level 15, State 1, Line 5
Incorrect syntax near the keyword ‘UNION’.

Ooopps…… I am unable to execute it.

Resolution:
It is very simple to resolve, just add one more column with any sorting number… either 1,2,3 or A,B,C and order on the basis of this column. Let me demonstrate it.


Conclusion :

Remember, whenever you use UNION / UNION ALL and have to order by each table separately, just add one more column with any sorting value and order by on the basis of this column.

Источник

Обсуждение: «UNION ALL» is failing

«UNION ALL» is failing

Re: «UNION ALL» is failing

Re: «UNION ALL» is failing

Re: «UNION ALL» is failing

Joy Smith writes:
> column types are the same so I don’t know why this ‘union all’ is failing.

It’s a syntax error — got nothing to do with column types.

I think what you need to do is parenthesize the first subquery. ORDER
BY isn’t allowed to be attached to a UNION subquery otherwise. You’re
probably going to need to parenthesize the second subquery too —
otherwise it will think that that ORDER BY applies to the UNION result,
not the subquery.

I don’t offhand remember the syntactic precedence of WITH versus UNION,
but trying to attach WITHs to the subqueries might be another reason to
need parentheses.

Re: «UNION ALL» is failing

On Fri, 2011-08-26 at 09:28 -0400, Joy Smith wrote:
> column types are the same so I don’t know why this ‘union all’ is failing.
> Any ideas?
>

You cannot have an ORDER BY before the UNION ALL. The manual says:

[ WITH [ RECURSIVE ] with_query [, . ] ]
SELECT [ ALL | DISTINCT [ ON ( expression [, . ] ) ] ]
* | expression [ [ AS ] output_name ] [, . ]
[ FROM from_item [, . ] ]
[ WHERE condition ]
[ GROUP BY expression [, . ] ]
[ HAVING condition [, . ] ]
[ WINDOW window_name AS ( window_definition ) [, . ] ]
[ < UNION | INTERSECT | EXCEPT >[ ALL ] select ]
[ ORDER BY expression [ ASC | DESC | USING operator ] [ NULLS
< FIRST | LAST >] [, . ] ]
[ LIMIT < count | ALL >]
[ OFFSET start [ ROW | ROWS ] ]
[ FETCH < FIRST | NEXT >[ count ] < ROW | ROWS >ONLY ]
[ FOR < UPDATE | SHARE >[ OF table_name [, . ] ] [ NOWAIT ] [. ]
]

See the ORDER AFTER the (one or many) UNION? you didn’t follow this, so
you have a syntax error.

Источник

UNION vs. UNION ALL in SQL: What’s the Difference?

Difference?

UNION and UNION ALL are both used to retrieve records from multiple tables. This article will detail the differences between the two, allowing you to make the best choice for each unique scenario.

You can use SQL’s UNION and UNION ALL commands to get data from multiple tables in your database. It’s a common use case, considering that most databases have many tables. Both UNION and UNION ALL are known as set operators. In SQL, set operators combine the results of two or more queries into a single result. You can read more about set operators in this article.

When comparing UNION vs. UNION ALL , there is one major difference:

  • UNION only returns unique
  • UNION ALL returns all records, including duplicates.

If you feel like you would benefit from a well-structured, comprehensive course that covers foundational SQL, consider this SQL Basics course from LearnSQL.

UNION vs. UNION ALL: Syntax

The syntax of both UNION variants is very similar. Let’s look at them individually, starting with UNION.

UNION Syntax

Remember, UNION combines the result set of two or more SELECT statements, showing only distinct values.

The SQL syntax below shows a UNION occurring between two different tables; the columns in both SELECT statements are of the same or matching data types.

The WHERE clause shown is an optional inclusion:

SQL UNION ALL Syntax

Remember, UNION ALL combines the results of two or more SELECT statements, showing all values, including duplicates if they exist.

The SQL syntax below shows a UNION ALL occurring between two different tables. Once again, the columns in the SELECT are of the same or matching data types and the WHERE clause is optional:

SQL UNION and UNION ALL Explained

There are several usage rules for UNION and UNION ALL . Failure to adhere to these rules will result in error messages:

  • The number of columns used in your first query and your second query must be the same and the data types (e.g. INT, VARCHAR, etc.) must match.
  • The column names included in both queries can differ; when this is the case, the resulting dataset will show the column names from the first query.
  • When using SQL aliases in conjunction with UNION and UNION ALL , you only need to include the alias with the first query. Including it with the second query will not cause an error, but it will also have no impact on the output.

You can use UNION and UNION ALL to combine tables that do not have any columns in common. This use case is covered in this article on how to join tables without a common column.

SQL UNION vs UNION ALL: Example

Let’s look at a practical example to gain greater understanding of UNION vs. UNION ALL . Imagine we have a database with information on several clubs. Each table will show the members of that club and what location they attend. Each club may have several different branches or locations where they meet. The first table is for the book_club . It contains the name of club members and what location they attend:

name location
John Fair Street
Mary Fair Street
Paul West Street

Similarly, the rowing_club contains the name of club members and what location they attend.

name location
Mary Fair Street
Samantha Fair Street
Paul West Street

Now that we have our tables, let’s write our SQL query. Using the UNION syntax, we get the following query:

UNION first performs a sorting operation and eliminates the records that are duplicated across all columns before finally returning the combined data set. You can see that we use columns of the same data type and SELECT the same number of columns in each query. This follows the rules of using UNION and should execute without an error.

Running this query produces the following result:

name location
John Fair Street
Mary Fair Street
Paul West Street
Samantha Fair Street

There we have it! All of the members from both clubs!

Now let’s alter the query and change UNION to UNION ALL :

With UNION ALL in place, we can expect the results to include duplicates. Let’s execute this new query and observe the output:

name location
John Fair Street
Mary Fair Street
Paul West Street
Mary Fair Street
Samantha Fair Street
Paul West Street

Can you spot all of the duplicate records? Compare this output to our original two tables. You can see that every row was included.

UNION or UNION ALL – Which Should You Choose?

Now that you know how to use both UNION and UNION ALL , you’re probably wondering which one is best for your situation. One thing to consider is the fact that UNION removes duplicate records, which can impact the performance of your query.

If you’re wondering which variant to use, remember:

  • Using UNION effectively performs a SELECT DISTINCT on the results set.
  • If you know that all of the records returned by UNION are going to be unique, use UNION ALL ; it will be faster. This is especially relevant for larger datasets.

Write Complex Queries with UNION and UNION ALL

We’ve covered the differences between UNION and UNION ALL and why you might choose one or the other. With this information, you can now retrieve data from two or more tables in your database. Both UNION and UNION ALL play an important role in the use of recursive queries, a more advanced topic that is covered in great detail in our Recursive Queries course.

Don’t forget to bookmark this page so you can have easy access to the explanations and examples of UNION vs. UNION ALL. Also, consider saving this page of our SQL Cookbook, which explains how to combine the results of two queries in SQL. This knowledge can take your SQL queries to the next level, helping you handle complex use cases with ease!

Источник

SQL UNION Operator

The SQL UNION Operator

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

UNION Syntax

UNION ALL Syntax

The UNION operator selects only distinct values by default. To allow duplicate values, use UNION ALL :

Note: The column names in the result-set are usually equal to the column names in the first SELECT statement.

Demo Database

In this tutorial we will use the well-known Northwind sample database.

Below is a selection from the «Customers» table:

CustomerID CustomerName ContactName Address City PostalCode Country
1

Alfreds Futterkiste Maria Anders Obere Str. 57 Berlin 12209 Germany 2 Ana Trujillo Emparedados y helados Ana Trujillo Avda. de la ConstituciГіn 2222 MГ©xico D.F. 05021 Mexico 3 Antonio Moreno TaquerГ­a Antonio Moreno Mataderos 2312 MГ©xico D.F. 05023 Mexico

And a selection from the «Suppliers» table:

SupplierID SupplierName ContactName Address City PostalCode Country
1 Exotic Liquid Charlotte Cooper 49 Gilbert St. London EC1 4SD UK
2 New Orleans Cajun Delights Shelley Burke P.O. Box 78934 New Orleans 70117 USA
3 Grandma Kelly’s Homestead Regina Murphy 707 Oxford Rd. Ann Arbor 48104 USA

SQL UNION Example

The following SQL statement returns the cities (only distinct values) from both the «Customers» and the «Suppliers» table:

Example

Note: If some customers or suppliers have the same city, each city will only be listed once, because UNION selects only distinct values. Use UNION ALL to also select duplicate values!

SQL UNION ALL Example

The following SQL statement returns the cities (duplicate values also) from both the «Customers» and the «Suppliers» table:

Example

SQL UNION With WHERE

The following SQL statement returns the German cities (only distinct values) from both the «Customers» and the «Suppliers» table:

Example

SQL UNION ALL With WHERE

The following SQL statement returns the German cities (duplicate values also) from both the «Customers» and the «Suppliers» table:

Example

Another UNION Example

The following SQL statement lists all customers and suppliers:

Example

Notice the «AS Type» above — it is an alias. SQL Aliases are used to give a table or a column a temporary name. An alias only exists for the duration of the query. So, here we have created a temporary column named «Type», that list whether the contact person is a «Customer» or a «Supplier».

Источник

Читайте также:  Subini str gh1 fs прошивка видеорегистратора
Smartadm.ru
Adblock
detector