Answer: SQL data types define that what type of data; a column can have in a table in SQL Database. Each column in a table has column name and its data type. Based on the requirement and design of database table, SQL Developer decides what data type, a column should have during creating a table. […]
Explain UNION and UNION ALL SQL Clause with example
Answer includes concept and difference between union and union all sql clause with example. Also, difference between union and join as a note has been included. Answer: UNION and UNION ALL: Used to combine the result set of 2 or more SELECT statements. UNION sql statement returns sorted result set with unique (UNION effectively […]
What are DDL and DML Commands in SQL with Examples
DDL and DML commands in SQL with examples should include definitions and difference between DDL Commands and DML commands in sql and important points. Also, 2 more command types TCL and DCL will be explained. DDL Commands: DDL means Data Definition Language. It is used to create and modify the structure of database objects in […]
Explain Default Constraint in SQL with Example and Uses
DEFAULT constraint in SQL is used to insert an automatic default value into a column of a table. If we don’t use default value constraint, then value of column will be NULL. We will answer this question with default constraint in SQL server with example and explanation that how to use it and when to […]
Difference between delete drop and truncate – Nicely Explained
Difference between drop, delete and truncate in SQL database is frequently asked interview question. DELETE removes rows one by one depending upon WHERE condition or delete all rows if there is no WHERE condition. TRUNCATE removes all rows at once and DROP command removes a table or database completely from database. In some situations, it […]
Explain Aggregate and Scalar functions in SQL
Answer includes, what is scalar functions in SQL and aggregate functions with examples and difference between scalar and aggregate functions. SQL Scalar functions: SQL scalar functions return a single value, based on the input value. For example, if we have to calculate the length of the string or want to convert letters in upper case or […]