Sql commands worked out in sql plus with screen shots
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This document discusses various SQL commands used in SQL Plus including creating a table, altering table columns, inserting records, retrieving data using queries, joining tables, and aggregating data using group by and having clauses. It provides examples of creating a PERSONS table, modifying columns, inserting sample data, querying for highest, lowest, and average salaries, demonstrating inner joins between tables, and using group by with aggregate functions to retrieve statistics grouped by customer.
Sql commands worked out in sql plus with screen shots
- 1. SQL Commands executed in SQL Plus Sunil Kumar Gunasekaran
- 2. 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; Page 1
- 3. After all the modifications done to the table Sample of records into the table using INSERT command Inse Page 2
- 4. The table with the values loaded is shown below Page 3
- 5. 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 Page 4
- 6. 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 Page 5
- 7. 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. Page 6
- 8. 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.eorderid, 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_IdONumber 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 Page 7
- 9. 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. Page 8