SQL QUERIES EXAMPLES PDF

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Sometimes need to eliminate duplicates in SQL queries. □ Can use DISTINCT keyword to eliminate duplicates. □ Example: “Find the number of branches that. A keyword refers to an individual SQL element. For example, SELECT and. FROM are keywords. A clause is a part of an SQL statement. For example. SELECT. This is perhaps the most widely used of SQL queries examples. In the example below, we are extracting the “Student_ID” column or attribute from the table.


Sql Queries Examples Pdf

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𝗣𝗗𝗙 | This book offers a short reference tutorial for database engineers and programmers that SQL Queries - Returning Top Elements. Glossary of commonly used SQL commands. Codecademy CASE statements are used to create different outputs (usually in the SELECT statement). It is SQL's . Before you start practicing with various types of examples given in this tutorial, I am assuming that you are .. SQL ─ SELECT Database, USE Statement.

What are all different types of collation sensitivity? Following are different types of collation sensitivity -. Case Sensitivity — A and a and B and b. Accent Sensitivity. Kana Sensitivity — Japanese Kana characters. Width Sensitivity — Single byte character and double byte character. Advantages and Disadvantages of Stored Procedure?

Cross JOIN or Cartesian Product

Stored procedure can be used as a modular programming — means create once, store and call for several times whenever required. This supports faster execution instead of executing multiple queries. This reduces network traffic and provides better security to the data. Disadvantage is that it can be executed only in the Database and utilizes more memory in the database server. Online Transaction Processing OLTP manages transaction based applications which can be used for data entry, data retrieval and data processing.

OLTP makes data management simple and efficient. Example — Bank Transactions on a daily basis.

SQL clause is defined to limit the result set by providing condition to the query. This usually filters some rows from the whole set of records. What is recursive stored procedure? A stored procedure which calls by itself until it reaches some boundary condition. This recursive function or procedure helps programmers to use the same set of code any number of times. What is Union, minus and Interact commands? UNION operator is used to combine the results of two tables, and it eliminates duplicate rows from the tables.

MINUS operator is used to return rows from the first query but not from the second query. Matching records of first and second query and other rows from the first query will be displayed as a result set.

Top 50 SQL Interview Questions & Answers

ALIAS name can be given to a table or column. Select st. StudentID, Ex. Result from student st, Exam as Ex where st. StudentID Here, st refers to alias name for student table and Ex refers to alias name for exam table. DROP command removes a table from the database and operation cannot be rolled back.

What are aggregate and scalar functions? Aggregate functions are used to evaluate mathematical calculation and return single values. This can be calculated from the columns in a table.

Scalar functions return a single value based on the input value. Example -. Aggregate — max , count - Calculated with respect to numeric.

How can you create an empty table from an existing table? Example will be -.

How to fetch common records from two tables? Common records result set can be achieved by -. Select studentID from student.

How to fetch alternate records from a table? What is the difference between Cluster and Non-Cluster Index? Clustered index is used for easy retrieval of data from the database by altering the way that the records are stored. Database sorts out rows by the column which is set to be clustered index.

A nonclustered index does not alter the way it was stored but creates a complete separate object within the table. It point back to the original table rows after searching. What is Datawarehouse?

Datawarehouse is a central repository of data from multiple sources of information. Those data are consolidated, transformed and made available for the mining and online processing. Warehouse data have a subset of data called Data Marts. What is Self-Join?

Sql queries interview questions pdf

Self-join is set to be query used to compare to itself. This is used to compare values in a column with other values in the same column in the same table. What is Cross-Join? Cross join defines as Cartesian product where number of rows in the first table multiplied by number of rows in the second table.

What is user defined functions? User defined functions are the functions written to use that logic whenever required. It is not necessary to write the same logic several times. Instead, function can be called or executed whenever needed.

SQL Cheat Sheet

What are all types of user defined functions? Three types of user defined functions are. Scalar Functions. Inline Table valued functions.

Multi statement valued functions. Scalar returns unit, variant defined the return clause.

Managing tables

Other two types return table as a return. What is collation? Collation is defined as set of rules that determine how character data can be sorted and compared. This can be used to compare A and, other language characters and also depends on the width of the characters.

ASCII value can be used to compare these character data. What are all different types of collation sensitivity? Following are different types of collation sensitivity -.

Case Sensitivity — A and a and B and b. Accent Sensitivity. Kana Sensitivity — Japanese Kana characters. Width Sensitivity — Single byte character and double byte character. Advantages and Disadvantages of Stored Procedure? Stored procedure can be used as a modular programming — means create once, store and call for several times whenever required. This supports faster execution instead of executing multiple queries.

This reduces network traffic and provides better security to the data. Disadvantage is that it can be executed only in the Database and utilizes more memory in the database server. Online Transaction Processing OLTP manages transaction based applications which can be used for data entry, data retrieval and data processing.Stored procedure can be used as a modular programming — means create once, store and call for several times whenever required.

These calculations are done from the columns in a table. Scalar returns unit, variant defined the return clause.

Displaying Internal Tables Internal tables are formed as a by-product of a user-action and are usually not accessible. Technically, if you're sending only one statement to the back end, you don't need the statement terminator; if you're sending more than one, you need it.

Following are different types of collation sensitivity -. Write an SQL query to show the current date and time. Click below to know more.

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