NCERT Solutions Class 12 Computer Science Structured Query Language. NCERT book for Computer Science in class 12 is strongly recommened by teachers and the CBSE and NCERT boards. Please download the NCERT solutions for class 12 Computer Science free in PDF made by teachers of the best schools in India. These solutions are carefully compiled to give detailed understanding of the concepts and also steps of solutions. The NCERT solutions are free to download in pdf format. Please refer to the download link below to download the pdf file and also refer to other chapters and subjects to get the solutions to Computer Science NCERT book questions and exercises.
Chapter - Structured Query Language
Question 1: Differentiate between delete and drop table command ?
Аnswer: DELETE command is used to remove information from a particular row or rows. If used without any condition, it will delete all row information but not the structure of the table. It is a DML command. DROP table command is used to remove the entire structure of the table and information. It is a DDL command.
Question 2: What is the use of wildcard ?
Аnswer: The wildcard operators are used with the LIKE operator to search a value similar to a specific pattern in a column. There are 2 wildcard operators. % – represents 0,1 or many characters – = represents a single number or character
Question 3: Write SQL query to add a column total price with datatype numeric and size 10, 2 in a table product.
Аnswer: ALTER TABLE product ADD total price number
Question 4: While creating table ‘customer’, Rahul a forgot to add column ‘price’. Which command is used to add new column in the table. Write the command to implement the same.
Аnswer: ALTER TABLE customer ADD price number(10,2)
Question 5: Deepika wants to remove all rows from the table BANK. But he needs to maintain the structure of the table. Which command is used to implement the same ?
Аnswer: DELETE FROM BANK
Question 6: Sonal needs to display name of teachers, who have “0” as the third character in their name.She wrote the following query. Select name from teacher where name = “$$0?”; But the query isn’t producing the result. Identify the problem.
Аnswer: The wildcards are incorrect. The corrected query is SELECT name FROM teacher
WHERE name LIKE’ _ _ 0%’
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