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A migration to add unique constraint to a combination of columns
...aintToShipments < ActiveRecord::Migration
def up
execute <<-SQL
alter table shipments
add constraint shipment_tracking_number unique (tracking_number, carrier);
SQL
end
def down
execute <<-SQL
alter table shipments
drop constraint if exis...
T-SQL get SELECTed value of stored procedure
In T-SQL, this is allowed:
4 Answers
4
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Is having an 'OR' in an INNER JOIN condition a bad idea?
...low query (several minutes on two tables with only ~50,000 rows each, on SQL Server 2008 if it matters), I narrowed down the problem to an OR in my inner join, as in:
...
How to order by with union in SQL?
...er the results of the select statement referencing that subselect. Per the SQL Standard, the order of results is undefined barring an explicit order by clause. That first select in your example probably returns its results in the order returned by the subselect, but it is not guaranteed. Further, th...
Generate full SQL script from EF 5 Code First Migrations
...s://docs.microsoft.com/en-us/ef/core/managing-schemas/migrations/#generate-sql-scripts
There are several options to this command.
The from migration should be the last migration applied to the database before running the script. If no migrations have been applied, specify 0 (this is the default).
T...
Convert INT to VARCHAR SQL
...trying to use a varchar where an int is needed. You need write your actual SQL statement for us to help you.
– Tobberoth
Nov 14 '13 at 14:10
14
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Aggregate function in an SQL update query?
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I know the question is tagged SQL Server but be careful with UPDATE with JOIN if you are using PostgreSQL. @JBrooks answer won't work :
UPDATE t1
SET t1.field1 = t2.field2Sum
FROM table1 t1
INNER JOIN (...) as t2
on t2.field3 = t1.field3
You will hav...
How do you use script variables in psql?
In MS SQL Server, I create my scripts to use customizable variables:
13 Answers
13
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How do I do multiple CASE WHEN conditions using SQL Server 2008?
What I'm trying to do is use more than one CASE WHEN condition for the same column.
10 Answers
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SQLiteDatabase.query method
I am using the query method of SQLiteDatabase. How do I use the query method?
5 Answers
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