The set of all distinct rows from two or more result sets.

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Optimizing a union query

SELECT id FROM user WHERE id IN ( 2,3,4,7,9,21,23,45,324,12,43,254 ) UNION SELECT DISTINCT user_id FROM workgroup_users WHERE workgroup_id IN ( 1,345,34,654,213,123,5,2,3,4 ) I know we should not ...
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How to improve performance when joining against coalesce

In an effort to remove a caching layer from our application, I'm building a number of views to encapsulate the different ways a user can have access to a piece of content - one per "rule" of access. ...
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Does union all have an enforced ordering

I know that a union does a de-duplication so can jumble the results, but I can't find a definitive answer for union all Example query select id from ( select id from table where id = 1 union all ...
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Footer with counter of records, using union of query

I have a report that has a header (display the current date), I use UNION to join the header with the main query that returns multiple records, it has 10 columns. After that another UNION for joining ...
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43 views

Sum of nested group query

I'm very new to SQL, so please bear suggest improvements anywhere. I have a PaymentsReceived table like this (simplified to only what is relevant) AccountID refrerences Accounts(ID) PaymentDate ...
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Performance of VIEWs with UNIONs in different databases

For various corporate and historical and replicating reasons, I have multiple databases that contain similar-structured tables, holding the main production data used as a source for other home-made ...
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Combining 2queries: One filtered Users on Role, One Select users with only one specific role

First query: Selects All users with specific rid ( 3 or 4 or 19 or ...). SELECT u.uid AS uid, u.name AS name, fn.field_full_name_value AS field_full_name_value FROM users u LEFT OUTER ...
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Optimization of an old query multiple unioned subqueries

I am currently in the process of optimizing a large query that was written for oracle 8i. My company currently uses oracle 10g which gives us a lot of options for optimization. Please Reference the ...