Summary of "String Functions in SQL | Functions in SQL | SQL Tutorial in Hindi 7"

Summary of Main Ideas and Concepts

Introduction to Functions in SQL
Functions are predefined keywords or objects in SQL that perform specific tasks. They accept input parameters, execute an action, and return an output. There are two types of functions:
- System Defined Functions: Built-in functions like rand, round, Upper, and Lower.
- User Defined Functions: Custom functions created by users for specific tasks.
String Functions
String Functions operate on string data types, which include alphanumeric values and special characters. Common String Functions discussed include:
- Upper: Converts all characters in a string to uppercase.
- Lower: Converts all characters in a string to lowercase.
- Length: Returns the number of characters in a string.
- Substring: Extracts a portion of a string based on specified positions.
- Replace: Replaces occurrences of a specified substring within a string.
- Trim: Removes leading and trailing spaces from a string.
Practical Implementation
The speaker demonstrates how to use String Functions with an example of a customer table in SQL. Examples include:
- Using Upper and Lower to change case.
- Using Length to find the number of characters in a string.
- Using substring to extract specific characters from a string.
- Using concat to combine first and last names.
- Using replace for data cleaning and trim to remove unwanted spaces.
Resources
The speaker mentions an official document detailing String Functions and operators in SQL, suggesting viewers search for "String Functions and operators Postgres" for more information.

Methodology / Instructions

To convert a string to uppercase:

SELECT Upper(column_name) FROM table_name;

To convert a string to lowercase:

SELECT Lower(column_name) FROM table_name;

To find the Length of a string:

SELECT Length(column_name) FROM table_name;

To extract a substring:

SELECT SUBSTRING(column_name FROM start_position FOR Length) FROM table_name;

To concatenate strings:

SELECT CONCAT(first_name, ' ', last_name) FROM table_name;

To replace a substring:

SELECT REPLACE(column_name, 'old_substring', 'new_substring') FROM table_name;

To trim spaces:

SELECT TRIM(column_name) FROM table_name;

Speakers/Sources Featured

The video is presented in Hindi, but no specific speaker names are mentioned in the subtitles. The content appears to be instructional and educational, likely aimed at learners of SQL.