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It does not matter if you use COLLATE in the column definition or (for example) in the ORDER BY clause, the price you pay is always the same. The reason is that the collation has no influence on how the strings are stored, only on how they are compared, which happens at query time. Some collations are more expensive than others, and the cheapest is C, so ...


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While not an expert on PostgreSQL collations, I have used PostgreSQL a little bit (I work mostly with SQL Server) and do not see how this particular info would/could be different than what I am about to describe: Short answer: It Depends (standard answer). Actual answer: specifying a collation at the column level (assuming that the collation is completely ...


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you can join on table_C SELECT nameC, nameA, nameB FROM table_Ref r INNER JOIN table_A a ON r.idA=a.idA INNER JOIN table_B b ON r.idB=b.idB INNER JOIN table_C c ON a.idC=c.idC;


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For MySQL i found this article from may 2018: https://mysqlserverteam.com/mysql-8-0-innodb-now-supports-instant-add-column/ MySQL 8.0: InnoDB now supports Instant ADD COLUMN Dictionary, InnoDB, MySQLDDL operationBin Su Instant DDL has been one of the most requested InnoDB features for a very long time. With ever larger and rapidly growing ...


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In Postgres nothing really happens. It just adds a row to the system catalogs so that it knows that you added a column. It doesn't even touch the table data. So even on a table with a billion rows this would only take a few milliseconds once it could obtain the exclusive lock on the table. Starting with Postgres 11, this even is the case when adding a ...


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Forced parametrization is on but doesn't seem to have an effect on this query, probably by the way it is executed. That's correct, forced paramterization doesn't work here because the query has "already been parameterized on the client-side application" (source). In other words, the problem is that there are two actual parameters, so the embedded date and ...


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It sounds like you have encountered this bug with the SQL Server 2014 ("new") cardinality estimator: Identifying SQL Server 2014 New Cardinality Estimator issues and Service Pack 1 improvement The specific bug was fixed in SQL Server 2014 SP1, per this KB: When the join predicate uses other conditions than equality or a combination of equalities, the ...


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