Content

• SQL update
• SQL delete
• SQL Min & Max
• SQL Count, Avg, Sum
• SQL like

SQL update

The UPDATE statement is used to modify the existing records in a table.

UPDATE table_name SET column1 = value1, column2 = value2, ... WHERE condition;

SQL delete

The DELETE statement is used to delete existing records in a table.

DELETE FROM table_name WHERE condition;

SQL Min & Max

The MIN() function returns the smallest value of the selected column.

SELECT MIN(column_name) FROM table_name WHERE condition;

The MAX() function returns the largest value of the selected column.

SELECT MAX(column_name) FROM table_name WHERE condition;

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SQL Count, Avg, Sum

The COUNT() function returns the number of rows that matches a specified criteria.

SELECT COUNT(column_name) FROM table_name WHERE condition;

The AVG() function returns the average value of a numeric column.

SELECT AVG(column_name) FROM table_name WHERE condition;

The SUM() function returns the total sum of a numeric column.

SELECT SUM(column_name) FROM table_name WHERE condition;

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SQL Like

The LIKE operator is used in a WHERE clause to search for a specified pattern in a column.

There are two wildcards often used in conjunction with the LIKE operator:

• % - The percent sign represents zero, one, or multiple characters
• _ - The underscore represents a single character

SELECT column1, column2, ... FROM table_name WHERE column LIKE pattern;

LIKE Operator	Description
WHERE CustomerName LIKE 'a%'	Finds any values that start with "a"
WHERE CustomerName LIKE '%a'	Finds any values that end with "a"
WHERE CustomerName LIKE '%or%'	Finds any values that have "or" in any position
WHERE CustomerName LIKE '_r%'	Finds any values that have "r" in the second position
WHERE CustomerName LIKE 'a_%_%'	Finds any values that start with "a" and are at least 3 characters in length
WHERE ContactName LIKE 'a%o'	Finds any values that start with "a" and ends with "o"