SQL Commands executed in SQL Plus

Sunil Kumar Gunasekaran

Creating table PERSONS1013 with the following Attribute names

Altering the Column name of the table P_ID to include NOT NULL and PRIMARY KEY status

Adding another column SALARY with data type as Number;

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After all the modifications done to the table

Sample of records into the table using INSERT command

Inse

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The table with the values loaded is shown below

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Getting the details of the record having the highest salary

Getting the name of the person with the highest salary

Getting the name of the person with minimum salary

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Getting the names of persons with salary greater than the average salary

The nested statements are used when there is one to one relationship between person and salary.

Need to work out on Inner Join Outer Join and Natural Join and other functions and update here to be done or revised before any interview.

Dropping the whole table using DROP DDL command

Deleting a particular record

Using Group by with a function to group by the entities based on the function;

Note that only Sum and average require group by since

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This is the Orders table for the above GROUP BY function execution.

The requirement is that there need to be a customer and many orders placed by him and hence many orderprices. If we want info of the max min avg sum of the orderprices placed by each customer, then use group by along with the functions.

Usage of Having

Having and group by are used in one t omany relationship between customer and orderprice

This is similar to where only that the aggregate functions can be used in having and aggregate functions cannot be used in where.

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Note that the having can hold expressions involving aggregate functions

INNER JOIN

There are two tables. Table 1 having customer firstr name last name address and city and P_ID;

The second table has details of order i.e orderid, order number and P_ID.

We need customer first name and customer last name and the order number of customers who made orders present in the Persons table. Hence we use inner join for this.

JOINS

Consider the following Persons table and Orders table. They have in common PID

Customer Table has PIDs 1 2 and 3

Orders Table has PIDs 3 3 1 1 and 15

We are going to make a join based on this common key.

When the join is made, a appended table containing all the column headings appear.

PID LN FN Add City O_Id ONumber PID

First the common elements are filled in the above table. This forms inner join

If the remnants of first table is added to the common records, then it is LEFT JOIN

If remnants of right table is added to the common records ,then it is RIGHT JOIN

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If remnants of left and right are added to the common records, then it is FULL JOIN.

In all cases remember the appended table in mind and work out accordingly.

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