SQL Tutorial > SQL SUB QUERIES

Practice: SQL Subqueries & Unions

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  • A subquery is a query that returns one or more rows of data from a parent table.
  • An example of a common use for a subquery is to return the total amount of sales for each customer.

Subqueries are used to retrieve data from a table in SQL. They are also known as cross-joins.

There are many types of subqueries that can be used in SQL.

  • Example 1: With a subquery, we can retrieve data from the same table, but with different conditions.
  • Example 2: We can use a subquery to return all the rows that meet a certain condition.
  • Example 3: A subquery is useful when we need to select only one column from more than one table, but with different conditions.

Subqueries are used when you want to work with a subset of data in a SQL statement. They are typically used in SQL statements to filter, sort, and group data.

UNION ALL is a SQL Server command. It is used to combine multiple SELECT statements into a single SELECT statement. While UNION is used to combine rows from multiple tables, UNION ALL combines columns from the same table.

Subqueries are useful when you want to get the result of a query without having to use the SELECT statement. They can be used in different ways such as filtering data or grouping data by specific criteria.

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ruhina qureshi
5

Awesome Classes ,Both tutors explains the concept very nice

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Yadav Aakash
5

very useful thank you learnvern

A
Ashish
5

The course is very good. I have stuck at a point that how you create multiple rows with a single insert in sales.customer table. I get only one customer data. this table is related to bikestore data.

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nayazbasha sk
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very useful thank you learnvern

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Mahima Patel
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very usefull......thanks

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Priya Kushwaha
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Very Good trainer

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chanchal singh
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you guys are doing nice job. thanks

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Umesh Wankhede
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Not too much interactive

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Monesh Ram
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Well Explained in Every Chapters..

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GAJANAN DIGAMBAR MODE
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very easy to understand SQL its was dream to learn SQL. Thanx for Learnvern

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  3. What is DBMS
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  1. Filtering Data using Selection Command
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  10. How to use SQL Conditional Statements
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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
    29m 41s
  8. Assignment : SQL Joins
    15m 5s
  9. Assignment : SQL Functions 1
    13m 25s
  10. Assignment : SQL Functions 2
    9m 25s

  1. Practice: SQL Subqueries
    26m 41s
  2. Practice: SQL Subqueries & Unions
    22m 29s
  3. SQL Correlated Subqueries Part 1
    20m 21s
  4. SQL Correlated Subqueries Part 2
    30m 51s
  5. SQL Correlated Subqueries Part 3
    30m 45s
  6. SQL Correlated Subqueries Part 4
    25m 7s
  7. SQL Correlated Subqueries Part 5
    19m 42s
  8. Correlated Select, Update & Delete Queries
    33m 15s
  9. SQL Union
    18m 3s
  10. SQL EXCEPT & INTERSECT
    14m 33s
  11. Assignment : SQL SubQueries
    30m 7s

  1. SQL Pivot, UnPivot Practical Example - 1
    37m 28s
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  1. What are Views?
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    10m 17s

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

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    41m 2s
  2. Using Correlated Sub Query, Group By with Select Statement
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    23m 32s
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    23m 24s
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    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
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  10. SQL Delete - Types of Delete Operation Part -2
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  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
    22m 2s
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