Here’s a good article on tagging Database schemas: http://howto.philippkeller.com/2005/04/24/Tags-Database-schemas/ along with performance tests: http://howto.philippkeller.com/2005/06/19/Tagsystems-performance-tests/ Note that the conclusions there are very specific to MySQL, which (at least in 2005 at the time that was written) had very poor full text indexing characteristics.
You can get SQL server to select the last N rows with the following query: select * from tbl_name order by id desc limit N;
“Alter column position” in the PostgreSQL Wiki says: PostgreSQL currently defines column order based on the attnum column of the pg_attribute table. The only way to change column order is either by recreating the table, or by adding columns and rotating data until you reach the desired layout. That’s pretty weak, but in their defense, … Read more
Try this SELECT CONVERT(DECIMAL(10,2),YOURCOLUMN) such as SELECT CONVERT(DECIMAL(10,2),2.999999) will result in output 3.00
The SQL command is: ALTER TABLE <tablename> ADD CONSTRAINT <constraintname> UNIQUE NONCLUSTERED ( <columnname> ) See the full syntax here. If you want to do it from a Database Diagram: right-click on the table and select ‘Indexes/Keys’ click the Add button to add a new index enter the necessary info in the Properties on the … Read more
Note: As the original asker implied, if you are setting up two databases on the same machine you probably want to make two schemas instead – in that case you don’t need anything special to query across them. postgres_fdw Use postgres_fdw (foreign data wrapper) to connect to tables in any Postgres database – local or … Read more
Assuming this table: CREATE TABLE students ( student_id SERIAL PRIMARY KEY, player_name TEXT ); There are four different ways to define a foreign key (when dealing with a single column PK) and they all lead to the same foreign key constraint: Inline without mentioning the target column: CREATE TABLE tests ( subject_id SERIAL, subject_name text, … Read more
Standard SQL syntax is DROP TABLE table_name; IF EXISTS is not standard; different platforms might support it with different syntax, or not support it at all. In PostgreSQL, the syntax is DROP TABLE IF EXISTS table_name; The first one will throw an error if the table doesn’t exist, or if other database objects depend on … Read more
Here is one way to do this, using UNION ALL (See SQL Fiddle with Demo). This works with two groups, if you have more than two groups, then you would need to specify the group number and add queries for each group: ( select * from mytable where `group` = 1 order by age desc … Read more
Prior to Laravel 5, there was no Laravel native way of altering an existing table column using the schema builder. You’d need to use raw queries for this. However, as of Laravel 5 you can use: $table->string(‘foo’)->nullable(false)->change(); You must have the dbal dependency prior to running the above command: composer require doctrine/dbal