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LENGTH

Find the length of text.

LENGTH

LENGTH returns the number of characters in a text. It is used to filter by text length in conditions.

SELECT name, LENGTH(name) AS uzun FROM customers;

This query puts the character count next to each name.

name, LENGTH(name) AS uzun is selected from customers.

LENGTH — details

Some databases use LEN; the ANSI standard is LENGTH. Spaces are counted; trim first to ignore them.

Practice LENGTH

Select from customers those whose name is longer than 5 characters.

Starter code

query.sql
-- long names
SELECT name
FROM customers
WHERE

Sample solution

query.sql
SELECT name
FROM customers
WHERE LENGTH(name) > 5

Expected output

name
Ayşe
Ahmet

Questions and answers

Review the lesson questions together with their answers. To test yourself, solve the lesson interactively.

1 Text length

Question 
SELECT name, ____(name) FROM customers;
Answer 
SELECT name, LENGTH(name) FROM customers;

Explanation: LENGTH returns the number of characters in the text.

2 What does LENGTH return?

  • The number of rows
  • The number of bytes
  • The number of words
  • The number of characters Correct answer

Explanation: LENGTH returns the character count.

3 LENGTH: match the terms

Term Meaning
LENGTH length
UPPER uppercase
LOWER lowercase
TRIM trim

All lessons in Beginner

1 SELECT basics

  1. What is SELECT?
  2. Selecting all columns
  3. Selecting specific columns
  4. Column aliases with AS
  5. Literal values
  6. Summary - SELECT basics

2 WHERE filtering

  1. What is WHERE?
  2. Comparison operators
  3. AND and OR
  4. IN and BETWEEN
  5. Pattern matching with LIKE
  6. Summary - WHERE filtering

3 Ordering and limit

  1. ORDER BY
  2. ASC and DESC
  3. Multi-column ordering
  4. LIMIT
  5. OFFSET
  6. Summary - Ordering and limit

4 Project: CRUD app

  1. Project design
  2. Reading data
  3. Inserting data
  4. Updating data
  5. Deleting data

5 Data types

  1. Integer types
  2. Decimal types
  3. CHAR and VARCHAR
  4. DATE and TIME
  5. BOOLEAN
  6. Summary - Data types

6 Operators

  1. Arithmetic operators
  2. Comparison operators
  3. Logical operators
  4. IS NULL
  5. String concatenation
  6. Summary - Operators

7 String functions

  1. UPPER and LOWER
  2. LENGTH
  3. SUBSTRING
  4. TRIM
  5. CONCAT
  6. Summary - String functions

8 Project: Shopping cart

  1. Cart design
  2. Listing products
  3. Adding to cart
  4. Calculating total
  5. Removing from cart

9 Number functions

  1. ROUND
  2. CEIL and FLOOR
  3. ABS
  4. POWER and SQRT
  5. MOD
  6. Summary - Number functions

10 Date functions

  1. CURRENT_DATE and NOW
  2. EXTRACT
  3. Date arithmetic
  4. DATEDIFF
  5. Date formatting
  6. Summary - Date functions

11 NULL handling

  1. What is NULL?
  2. IS NULL
  3. COALESCE
  4. NULLIF
  5. Three-valued logic
  6. Summary - NULL handling

12 DISTINCT

  1. What is DISTINCT?
  2. DISTINCT on one column
  3. Multi-column DISTINCT
  4. DISTINCT with aggregates
  5. DISTINCT vs GROUP BY
  6. Summary - DISTINCT

13 INSERT

  1. INSERT basics
  2. Inserting into specific columns
  3. Multiple rows
  4. INSERT with SELECT
  5. DEFAULT values
  6. Summary - INSERT

14 UPDATE

  1. UPDATE basics
  2. Conditional UPDATE
  3. Multi-column UPDATE
  4. Calculated updates
  5. UPDATE pitfalls
  6. Summary - UPDATE

15 DELETE

  1. DELETE basics
  2. Conditional DELETE
  3. DELETE vs TRUNCATE
  4. Emptying a table
  5. Safe deletion
  6. Summary - DELETE

16 CREATE TABLE

  1. CREATE TABLE basics
  2. Column definitions
  3. NOT NULL
  4. DEFAULT
  5. PRIMARY KEY
  6. Summary - CREATE TABLE

17 Constraints

  1. UNIQUE constraint
  2. CHECK constraint
  3. FOREIGN KEY
  4. CASCADE
  5. Constraint management
  6. Summary - Constraints

18 Simple JOIN

  1. What is JOIN?
  2. INNER JOIN
  3. The ON clause
  4. Table aliases
  5. Multi-table JOIN
  6. Summary - Simple JOIN

19 Project: Inventory system

  1. Inventory design
  2. Product table
  3. Stock movements
  4. Stock report
  5. Low stock alert

20 Beginner final

  1. Customer query
  2. Order report
  3. Data update
  4. Table redesign