Notice: This page requires JavaScript to function properly.
Please enable JavaScript in your browser settings or update your browser.Apprendre SQL Where | Database & Introduction to Syntax
SQL Tutorial for Beginners
course content

Contenu du cours

SQL Tutorial for Beginners

SQL Tutorial for Beginners

1. Database & Introduction to Syntax
Meet the SQLSelect the Songs!SQL Select ColumnSQL DistinctSQL WhereChallenge WhereSQL And, Or, Not
2. SQL Aggregate Functions
SQL Min and MaxChallenge Min and MaxSQL Count, Sum, AvgChallenge Count
3. Filtering Statements
SQL NullSQL LikeChallenge LikeSQL BetweenSQL Order ByChallenge Order BySQL Group ByChallenge Group BySQL Top and LimitSQL AliasesSQL HavingChallenge HavingSQL Comments

book
SQL Where

You’ll need to filter your selected data very often, so you need to use WHERE keyword. After WHERE you put some condition or combination of them. Usually it is some column's values limitations.

For example, you want to select records where singer is AC/DC:


              
12

            
SELECT * FROM songs
WHERE singer = 'AC/DC'
copy

Another example of the query using the WHERE statement. It retrieves all records with a price column value greater than 100. The syntax is pretty easy to understand: WHERE price > 100.


              
12

            
SELECT * FROM songs
WHERE price > 100
copy

Here you can see the main syntax.

  • Use = to find fields which values are equal to some naming.
  • Use != or <> to find non-equal fields.
  • Use >, <, >=, <= for comparing.
  • Use single quotes 'Quotes' for string values.
  • Use () brackets for prioritization.

              
123

            
/* all records where year column is greater or equal than 1970*/
SELECT * FROM songs
WHERE year >= 1970
copy

For string values, you have to write them inside single quotes. Like 'ABBA', 'Toxic' etc. Check carefully string values in the condition statements: no extra spaces, correct capitalization (for example, Britney Spears is correct, not BRITNEY SPEARS or britney spears). Otherwise, you'll receive the Internal Server Error.

Tâche

Swipe to start coding

Select all records with Britney Spears as a singer. Change your query to select only Britney Spears songs' titles (not full records, only column title).

Solution

Switch to desktopPassez à un bureau pour une pratique réelleContinuez d'où vous êtes en utilisant l'une des options ci-dessous
Tout était clair ?

Comment pouvons-nous l'améliorer ?

Merci pour vos commentaires !

Section 1. Chapitre 5
toggle bottom row

book
SQL Where

You’ll need to filter your selected data very often, so you need to use WHERE keyword. After WHERE you put some condition or combination of them. Usually it is some column's values limitations.

For example, you want to select records where singer is AC/DC:


              
12

            
SELECT * FROM songs
WHERE singer = 'AC/DC'
copy

Another example of the query using the WHERE statement. It retrieves all records with a price column value greater than 100. The syntax is pretty easy to understand: WHERE price > 100.


              
12

            
SELECT * FROM songs
WHERE price > 100
copy

Here you can see the main syntax.

  • Use = to find fields which values are equal to some naming.
  • Use != or <> to find non-equal fields.
  • Use >, <, >=, <= for comparing.
  • Use single quotes 'Quotes' for string values.
  • Use () brackets for prioritization.

              
123

            
/* all records where year column is greater or equal than 1970*/
SELECT * FROM songs
WHERE year >= 1970
copy

For string values, you have to write them inside single quotes. Like 'ABBA', 'Toxic' etc. Check carefully string values in the condition statements: no extra spaces, correct capitalization (for example, Britney Spears is correct, not BRITNEY SPEARS or britney spears). Otherwise, you'll receive the Internal Server Error.

Tâche

Swipe to start coding

Select all records with Britney Spears as a singer. Change your query to select only Britney Spears songs' titles (not full records, only column title).

Solution

Switch to desktopPassez à un bureau pour une pratique réelleContinuez d'où vous êtes en utilisant l'une des options ci-dessous
Tout était clair ?

Comment pouvons-nous l'améliorer ?

Merci pour vos commentaires !

Section 1. Chapitre 5
Switch to desktopPassez à un bureau pour une pratique réelleContinuez d'où vous êtes en utilisant l'une des options ci-dessous
Nous sommes désolés de vous informer que quelque chose s'est mal passé. Qu'est-il arrivé ?
some-alt