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How to set a default value for a datetime column to record creation time in a migration?
Consider the table creation script below:
7 Answers
7
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Rails 3: Get Random Record
...ils 3 all examples will work. But using order RANDOM is quite slow for big tables but more sql-style
UPD. You can use the following trick on an indexed column (PostgreSQL syntax):
select *
from my_table
where id >= trunc(
random() * (select max(id) from my_table) + 1
)
order by id
limit 1...
How can I export the schema of a database in PostgreSQL?
...ed formats
--lock-wait-timeout=TIMEOUT fail after waiting TIMEOUT for a table lock
-?, --help show this help, then exit
Options controlling the output content:
-a, --data-only dump only the data, not the schema
-b, --blobs include large objec...
T-SQL: Selecting rows to delete via joins
...
DELETE TableA
FROM TableA a
INNER JOIN TableB b
ON b.Bid = a.Bid
AND [my filter condition]
should work
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MySQL - Rows to Columns
...e of terms that I'll use for the rest of this post. This will be the base table:
select * from history;
+--------+----------+-----------+
| hostid | itemname | itemvalue |
+--------+----------+-----------+
| 1 | A | 10 |
| 1 | B | 3 |
| 2 | A | ...
Hibernate error - QuerySyntaxException: users is not mapped [from users]
I'm trying to get a list of all the users from "users" table and I get the following error:
18 Answers
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Why is SELECT * considered harmful?
...work. This is especially true when someone adds new columns to underlying tables that didn't exist and weren't needed when the original consumers coded their data access.
Indexing issues. Consider a scenario where you want to tune a query to a high level of performance. If you were to use *, and ...
How can I select from list of values in SQL Server
...g them:
[MS official] https://docs.microsoft.com/en-us/sql/t-sql/queries/table-value-constructor-transact-sql
http://www.sql-server-helper.com/sql-server-2008/row-value-constructor-as-derived-table.aspx
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How to write a foreach in SQL Server?
...rforms better than a cursor and is simpler:
DECLARE @PractitionerList TABLE(PracticionerID INT)
DECLARE @PractitionerID INT
INSERT @PractitionerList(PracticionerID)
SELECT PracticionerID
FROM Practitioner
WHILE(1 = 1)
BEGIN
SET @PracticionerID = NULL
S...
Set NOW() as Default Value for datetime datatype?
I have two columns in table users namely registerDate and lastVisitDate which consist of datetime data type. I would like to do the following.
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