Single-column Indexes: A single-column index is created for only one column of a table. Q26. Write a SQL query to find the names of employees that begin with ‘A’? What do you mean by table and field in SQL? Collation is defined as a set of rules that determine how data can be sorted as well as compared. The OLTP system often follows decentralized planning to keep away from single points of failure. Thank You for sharing these interview questions.These are really helpful and essential questions for interview. They are very useful in places where we need to store temporary data. Q10. A table is structured with a set number of columns and a boundless number of rows. Since views are not virtually present, they take less space to store. Group functions work on the set of rows and returns one result per group. Thanks for sharing SQL questions and solution. What is the difference between SQL and MySQL? Answer : We can manage SQL Azure database using SQL server management server 2008 R2. Having Clause is only used with the GROUP BY function in a query whereas WHERE Clause is applied to each row before they are a part of the GROUP BY function in a query. These are some basic but very essential questions an Sql professional should know. Clustered index alters the way records are stored in a database as it sorts out rows by the column which is set to be clustered index whereas in a non clustered index, it does not alter the way it was stored but it creates a separate object within a table which points back to the original table rows after searching. There are various types of joins which are used to retrieve data between the tables. This course trains you on the core concepts & advanced tools and techniques to manage data and administer the MySQL Database. What is a unique constraint? This blog is the perfect guide for you to learn all the concepts related to SQL, Oracle, MS SQL Server and MySQL database. PostgreSQL is an object-relational database management systems (ORDBMS). Trigger in SQL is are a special type of stored procedures that are defined to execute automatically in place or after data modifications. With an additional 50 professionally written interview answer examples. Default constraint: It is used to define a default value for a column so that the default value will be added to all the new records if no other value is specified. These variables are the variables which can be accessed throughout the program. Example- In the Student table, Stu_ID is the primary key. SQL is an individual query that is used to execute DML and DDL commands. It takes a string as an argument and returns it by converting it into uppercase. When we apply Inner Join on these two tables, we will get only those records that are common to both Table A and Table B. Hence, such systems are generally used for data mining or maintaining aggregated historical data, and they are usually used in multi-dimensional schemas. These questions are really amazing, to preapre for an interview..Thanks. This is a one-stop resource through which you can avail the maximum benefit and prepare for job interviews easily. Required fields are marked *. The stuff function deletes a part of the string and then inserts another part into the string starting at a specified position. Q65. We can consolidate several SQL statements into a stored procedure and execute them whenever and wherever required. Pointers are used for physical data files, Stores data in the leaf nodes of the index, Never stores data in the leaf nodes of the index, By default, the primary key of a table is a clustered index, It can be used with the unique constraint on the table that acts as a composite key, Improves the performance of data retrieval, Should be created on columns used in Joins. There can also be relationships between separate tables (for example, customer to accounts). However, using the full load process, all the records are loaded in one batch after all the contents of the table have been erased. Relation or links are between entities that have something to do with each other. Constraints are used to specify some sort of rules for processing data and limiting the type of data that can go into a table. It allows you to perform various operations on the database such as CREATE, ALTER and DELETE objects. Almost all biggest names in the tech industry such as Uber, Netflix, Airbnb, etc. For example – UCASE(), NOW() are calculated with respect to string. Now, we will write a query for demonstrating the use of a primary key for the Employee table: A foreign key is an attribute or a set of attributes that references to the primary key of some other table. Kana Sensitivity: Japanese Kana characters. Now, we will see the major differences between clustered and non-clustered indexes: Now, in this ‘Top SQL Interview Questions’ blog, we will move on to the next question. Migrating a Database across platforms. Select studentID from student. In an AWS interview, you may come across basic as well as advanced AWS database interview questions. This also supports faster execution when compared to executing multiple queries. Thanks for sharing. It is a programming language for a database that uses SQL. A view is a virtual table which consists of a subset of data contained in a table. Are NULL values same as that of zero or a blank space? Truncate is used to delete all the rows from a table. Hence, with the delete command, we have the option of recovering the original. In this SQL Interview Questions blog, I will introduce you to the most frequently asked questions on SQL (Structured Query Language). 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