To delete information from a table, use DELETE statements.

DELETE Syntax

The DELETE statement requires the table name in the FROM clause and the row's primary key in the WHERE clause, as shown in the following example:

<delete_statement> ::= DELETE FROM <table_name> WHERE { Id = <expression> } [ { AND | OR } ... ]

<expression> ::=
  | @ <parameter> 
  | ?
  | <literal>

You can use the executeUpdate method of the Statement or PreparedStatement classes to execute data manipulation commands and retrieve the number of affected rows, as shown in the following example:

Connection connection = DriverManager.getConnection("jdbc:wordpress:URL=http://www.yourwordpresshost.com;User=yourUsername;Password=yourPassword;",);
String cmd = "DELETE FROM Categories WHERE Id = ?";
PreparedStatement pstmt = connection.prepareStatement(cmd);
pstmt.setString(1, "25");
int count=pstmt.executeUpdate();
connection.close();