SQL Tutorial > SQL INDEXES

What is SQL Index?

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Indexes are special lookup tables that can be used by the database search engine to speed up data retrieval. An index is just a reference to data in a table. A database index is analogous to the index in the back of a book.

Indexes are used to get data from a database faster than would otherwise be possible. The indexes are hidden from the users and are only used to speed up searches and queries. It's worth noting that updating a table with indexes takes longer than updating a table without them (because the indexes also need an update).

Individual lookup tables, known as indexes in SQL, are employed by the database search engine to speed up total data retrieval. An index in the table is used to speed up the total time it takes to search the database for specific data.

A SQL index is a quick lookup table for locating records that are often searched. An index is a data structure that is tiny, fast, and optimised for speedy lookups. It's great for linking relational tables and searching huge databases. It's worth noting that generating a primary key does not automatically result in the creation of a unique SQL index.

By generating pointers to where data is kept within a database, indexing makes it easier to query columns. Assume you need to locate a specific piece of data in a vast database. To retrieve this data from the database, the computer will search every row until it finds it.

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Hi Team, Why you didn't teach/learn how to write select query, even you shared 15 question for practice :(

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  1. Getting Started
    18m 54s

  1. SQL Datatypes
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  2. SQL Commands
    21m 59s
  3. What is DBMS
    27m 51s
  4. What is RDBMS
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  1. Database Relationships
    11m 35s
  2. Primary Key
    6m 50s
  3. Unique Key
    3m 34s
  4. Foreign Key
    4m 2s
  5. Difference between PK, UK and PK & FK
    6m 6s

  1. SQL Server Installation Step by Step
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  1. How to Create Database in SQL Server
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    5m 5s

  1. SQL Constraints
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    28m 12s

  1. Filtering Data using Selection Command
    31m 53s
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  1. Aggregate Functions in SQL for Data Analysis
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  8. Row Number Function
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  10. How to use SQL Conditional Statements
    4m 22s
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  12. SQL Practical with Examples
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  13. Assignment : SQL Date and Time
    15m 16s

  1. Type of Joins in SQL - INNER, LEFT
    21m 24s
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  3. SQL Joins Practical Session 1
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  4. SQL Joins Practical Session 2
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  5. SQL Joins Practical Session 3
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  6. SQL Joins Practical Session 4
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  7. SQL Joins Practical Session 5
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    13m 25s
  10. Assignment : SQL Functions 2
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  1. Practice: SQL Subqueries
    26m 41s
  2. Practice: SQL Subqueries & Unions
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  3. SQL Correlated Subqueries Part 1
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  5. SQL Correlated Subqueries Part 3
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  6. SQL Correlated Subqueries Part 4
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  8. Correlated Select, Update & Delete Queries
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  10. SQL EXCEPT & INTERSECT
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  11. Assignment : SQL SubQueries
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  1. SQL Pivot, UnPivot Practical Example - 1
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  1. What are Views?
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  2. Examples of SQL Views Part -1
    16m 41s
  3. Examples of SQL Views Part -2
    17m 47s
  4. Assignment : SQL Views
    10m 17s

  1. What is SQL Index?
    13m 29s
  2. SQL Index types
    24m 50s

  1. Create Tables using Select Statement
    41m 2s
  2. Using Correlated Sub Query, Group By with Select Statement
    40m 2s
  3. Using Group By and Having Clauses with Select Statement
    23m 32s
  4. Using Index Optimizer with Select Statement
    23m 24s
  5. Using Union with Select Statement
    35m 4s
  6. Adding Multiple Records with Insert Statement
    22m 42s
  7. SQL Insert - Considerations and Best Practices
    9m 19s
  8. Insertion from Multiple Tables
    22m 11s
  9. SQL Delete - Types of Delete Operation Part -1
    16m 41s
  10. SQL Delete - Types of Delete Operation Part -2
    11m 38s
  11. Assignment : SQL Insert, Update & Delete
    7m 24s

  1. Loading & Connecting Different Files in SQL
    11m 18s

  1. Course Summary
    9m 6s

  1. Interview Questions Part 1
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  1. Career Guideline
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