The problem is: change the name of the employee in the employee information table to another one. For example, change Zhang to Wang and only change the name without changing the name:
Update table name set field name = 'King' | substr (field name, 2, length (field name) where field name like 'sheet % ';
The table name is Recv, which contains the field no so that the no field is incrementing:
Create Sequence
Start with 1
Increment by 1;
Query the types of all user tables and their corresponding fields:
Select * From user_tab_columns;
Oracle uses SQL to query the remarks of table field columns:
Select comments
From user_col_comments
Where table_name = 'dept'
And column_name = 'deptno ';
Use an SQL statement to obtain the table structure of the specified Oracle table: 1. Select * From all_tab_columns where owner = 'use1' and table_name = 'B '; 2. DESC table name 3. Select column_name as fieldname, data_type as type, data_length as size, nullable as isnull from user_tab_columns where table_name = 'tablename'
Query the field type of a column in a table in the User table in the 'sale el' column:
Select * From user_tab_columns where table_name = 'dept' and column_name = 'deptno ';
