MySQL’s now() +1 day
You can use: NOW() + INTERVAL 1 DAY If you are only interested in the date, not the date and time then you can use CURDATE instead of NOW: CURDATE() + INTERVAL 1 DAY
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Extracting hours from a DateTime (SQL Server 2005)
SELECT DATEPART(HOUR, GETDATE()); DATEPART documentation
Are “from Table1 left join Table2” and “from Table2 right join Table1” interchangeable?
Select * from Table1 left join Table2 … and Select * from Table2 right join Table1 … are indeed completely interchangeable. Try however Table2 left join Table1 (or its identical pair, Table1 right join Table2) to see a difference. This query should give you more rows, since Table2 contains a row with an id which … Read more
CREATE TABLE IF NOT EXISTS equivalent in SQL Server [duplicate]
if not exists (select * from sysobjects where name=”cars” and xtype=”U”) create table cars ( Name varchar(64) not null ) go The above will create a table called cars if the table does not already exist.
Use variable with TOP in select statement in SQL Server without making it dynamic [duplicate]
Yes, in SQL Server 2005 it’s possible to use a variable in the top clause. select top (@top) * from tablename
Foreign key constraints: When to use ON UPDATE and ON DELETE
Do not hesitate to put constraints on the database. You’ll be sure to have a consistent database, and that’s one of the good reasons to use a database. Especially if you have several applications requesting it (or just one application but with a direct mode and a batch mode using different sources). With MySQL you … Read more
How to get the count of each distinct value in a column? [duplicate]
SELECT category, COUNT(*) AS `num` FROM posts GROUP BY category
MySQL: How to copy rows, but change a few fields?
INSERT INTO Table ( Event_ID , col2 … ) SELECT “155” , col2 … FROM Table WHERE Event_ID = “120” Here, the col2, … represent the remaining columns (the ones other than Event_ID) in your table.
Cannot delete or update a parent row: a foreign key constraint fails
The simple way would be to disable the foreign key check; make the changes then re-enable foreign key check. SET FOREIGN_KEY_CHECKS=0; — to disable them SET FOREIGN_KEY_CHECKS=1; — to re-enable them
How do I query using fields inside the new PostgreSQL JSON datatype?
Postgres 9.2 I quote Andrew Dunstan on the pgsql-hackers list: At some stage there will possibly be some json-processing (as opposed to json-producing) functions, but not in 9.2. Doesn’t prevent him from providing an example implementation in PLV8 that should solve your problem. (Link is dead now, see modern PLV8 instead.) Postgres 9.3 Offers an … Read more