Basic Statement

list up useful statements, just find the statement you need with ctrl+f

Reference: https://www.w3schools.com/sql/default.asp

This statement is for MySQL Syntax.

Select sub columns from the table

SELECT col1, col2
FROM table_name;

Select all columns from the table (* means all)

SELECT * FROM table_name;

Select sub columns who have distanct values

SELECT DISTINCT col1, col2
FROM table_name;

Filter records based on a condition

SELECT col1, col2
FROM table_name
WHERE condition;

Operator: =, >, <, >=, <=, <>, BETWEEN, LIKE(To find a pattern), IN(Multple values)

Connect several conditions with logical operator: AND, OR, NOT

Sort the table based on the col

SELECT col1, col2
FROM table_name
ORDER BY col1 ASC, col2 DESC; 

Insert new records into a table

INSERT INTO table_name (col1, col2)
VALUES (val1, val2);

Check for NULL

SELECT col1
FROM table_name
WHERE col1 IS NULL; # IS NOT NULL also can be used.

Update for modifying the existing records

UPDATE table_name
SET col1=val1, col2=val2
WHERE condition;

Under this condition, we modify the value from col1 with new value, so basically update statment is for changing the value in column.

Delete some records(row records)

DELETE FROM table_name WHERE condition;

Select top n data

SELECT col1
FROM table_name
WHERE condition
LIMIT number;

You can use more function like min, max, count, avg, and sum

Find the data which of column matches specific string pattern with regex.

SELECT col1, col2
FROM table_name
WHERE col1 LIKE pattern;

SELECT * FROM Customers
WHERE CustomerName LIKE 'a__%';

Aliases for giving name to table or column

(Because this statement is just temporary, so an alias only exists for the duration of that query.)

SELECT col1 AS alias_name 
FROM table_name;