sql intro
Estimated reading time: 1 minuteWhat is SQL
SQL Stands for Structure Query Language
. SQL was initially developed at IBM by Donald D. Chamberlin
and Raymond F. Boyce
in the early 1970s.[15] This version, initially called SEQUEL
(Structured English Query Language).
fun part
create / drop database
/* create database */
create database users;
/* drop / delete database */
drop database users;
create / drop table
create table table_name (
col_1 datatype,
col_2 datatype
....
)
/* drop / delete table */
drop table table_name
/* alter coulmn / adding new column */
alter table table_name
add column_name datatype;
/* drop column */
alter table table_name
drop column col_name;
Most uses command
- select
- update
- delete
- insert
- where
important
- is null
- is not null
- min(col_name)
- max(col_name)
- count(col_name)
- avg(col_name)
- sum(col_name)
- alias = as
insert
/* adding row */
insert into table_name (col_1,col_2,......)
values (value_1,value_2,....);
update
/* updating row data */
update table_name
set col_name = value , col_name = value .....
where condition;
delete
delete from table_name
where condition;
resource
- https://www.w3schools.com/sql/
- https://www.tutorialspoint.com/sql/
- http://www.sqlcourse.com
- http://www.dofactory.com/sql/
- http://www.sqltutorial.org/sql-cheat-sheet/
- wiki book pdf
- wikibook
- mysqltutorial