11th Day SQL

SQL Structured Query statement:

$ sqlplus/as sysdba into SQL as administrator under Oracle User

sql> alter user HR account unlock identified by HR; Unlock HR Users

Sql> Show user shows current administrator status

Sql> DESC Employees Show all columns of employees

Full screen editing function with Sqlplus:;

Sql> Ed

Go to full screen edit equivalent VI editor

Enter SQL command, save after exiting

sql>/execution

SQL Base query:

Query statements each query is the intersection of rows and columns

Filter criteria for Select Columns * represents all Columns

from which table

Row of the where row's filter condition Plus condition example id=90

Base SELECT statement:

Sql> SELECT * FROM Employees;

Sql> DESC Employees

Sql> Select Last_Name, SALARY, commission_pct from employees;

Sql> DESC Departments

Sql> Select department_id, department_name from departments;

spaces are aliased after the columns of the query :
Select salary,12*salary* (1+commission_pct) total wage from employees; The total salary is the alias of salary,12*salary* (1+commission_pct).

To construct a statement using hyphens:

Output the following employee information:

EmployeeID is ... at department. Total salary are ...

Select ' Employee name is ' | | last_name| | ' The department is ' department_id '

From Employees

where;

11th Day SQL