To find and delete duplicate rows from a table, you can execute the query below. Note that this is for Oracle. You can use it for other databases but you need to change the ‘rowid’ then. delete from table_name A where a.rowid > any ( select B.rowid from table_name B where A.column_name = B.column_name ); You need to change the ‘table_name’ by your table name an the...
Hi, I made a java program where much database queries are processed in MySQL. After some time running, I got an error message:
Sometimes, it could be handy to know in which tables a certain column name is specified. To do so, use the query below.
select distinct table_name
from information_schema.columns
where column_name in ('columnA','ColumnB')
and table_schema = 'YourDatabase';
Note: you need to fill in your own column names and table_schema. Enjoy!
In this post, I will tell you how to fix the error that PostgreSQL throws when you try to execute an SQL-statement.
On , you find two interesting tools for MySQL. A configuration wizard that recommends a MySQL configuration based on your server settings. There is also a query analyzer tool that analyzes your SQL query and provides feedback. To use the tools, you need to log in, but they are free! MySQL settings optimizer The MySQL optimizer will ask you to fill in your server configuration and database...
Sonar uses a Derby or H2 as default database. When running Sonar, it says that these databases may only be used for evaluation. Now, in this article, I will tell you how to change the default database and how to configure Maven to use it.
If you get the error How to fix ORA-01502: index or partition of such index is in usable state in Oracle. It is possible that an index is broken from a table.
When you get an error like: How to fix ORA-01654 unable to extend index in tablespace, then this article is for you!.
The problem in Oracle is that when you delete a record, Oracle will leave it blank. That’s a real waste of space when you delete thousands of records. So deleting records will not help to solve this problem.
If you are searching for a database manager tool that support multiple database types and is totally free? Then this article is for you.