- MySQL Mathematical Functions
- MySQL String Functions
- Basic MySQL Commands
- SQL Commands
- Common MySQL Column Types
- MySQL Command-Line
- Rapid Link to MySQL.com
- Well formatted Examples
- Credits
What | How |
---|---|
Count rows per group | COUNT(column / * ) |
Average value of group | AVG(column) |
Minumum value of group | MIN(column) |
Maximum value of group | MAX(column) |
Sum values in a group | SUM(column) |
Absolute value | abs(number) |
Rounding numbers | round(number) |
Largest integer not greater | floor(number) |
Smallest integer not smaller | ceiling(number) |
Square root | sqrt(number) |
nth power | pow(base,exponent) |
random number n, 0 < n < 1 | rand() |
sin (similar cos, etc.) | sin(number) |
What | How |
---|---|
Compare strings | strcmp(string1,string2) |
Convert to lower case | lower(string) |
Convert to upper case | upper(string) |
Left-trim whitespace (similar right) | ltrim(string) |
Substring of string | substring(string,index1,index2) |
Encrypt password | password(string) |
Encode string | encode(string,key) |
Decode string | decode(string,key) |
Get date | curdate() |
Get time | curtime() |
Extract day name from date string | dayname(string) |
Extract day number from date string | dayofweek(string) |
Extract month from date string | monthname(string) |
Official reference of SHOW syntax, DROP DATABASE and DROP TABLE.
What | How | Examples |
---|---|---|
List all databases | SHOW DATABASES; |
SHOW DATABASES; |
Create database | CREATE DATABASE database; |
CREATE DATABASE PhoneDB; |
Use a database | USE database; |
USE PhonDB; |
List tables in the database | SHOW TABLES; |
SHOW TABLES; |
Show the structure of a table | DESCRIBE table; , SHOW COLUMNS FROM table; |
DESCRIBE Animals; , SHOW COLUMNS FROM Animals; |
Delete a database (Careful!) | DROP DATABASE database; |
DROP DATABASE PhoneDB; |
Official reference of SELECT syntax.
Click on the What
entry to see the How
's and Examples
's code better formatted.
What | How | Examples |
---|---|---|
All columns | SELECT * FROM table; |
SELECT * FROM Students; |
Some columns | SELECT column1,column2,... FROM table; |
SELECT LastName, FirstName FROM Students; |
Some rows/columns | SELECT column1,column2,... FROM table [WHERE condition(s)]; |
SELECT LastName,FirstName FROM Students WHERE StudentID LIKE '%123%'; |
No Repeats | SELECT [DISTINCT] column(s) FROM table; |
SELECT DISTINCT LastName FROM Students; |
Ordering | SELECT column1,column2,... FROM table [ORDER BY column(s) [DESC]]; |
SELECT LastName,FirstName FROM Students ORDER BY LastName, FirstName DESC; |
Column Aliases | SELECT column1 [AS *alias1*], column2 [AS alias2], ... FROM table1; |
SELECT LastName,FirstName AS First FROM Students; |
Grouping | SELECT column1,column2,... FROM table [GROUP BY column(s)]; |
SELECT LastName,COUNT(*) FROM Students GROUP BY LastName; |
Group Filtering | SELECT column1,column2,... FROM table [GROUP BY column(s)] [HAVING condition(s)]; |
SELECT LastName,COUNT(*) FROM Students GROUP BY LastName HAVING LastName like '%son'; |
Joins | SELECT column1,column2,... FROM table1,table2,... [WHERE condition(s)]; |
SELECT LastName,Points FROM Students,Assignments WHERE AssignmentID=12 AND Students.StudentID=Assignments.StudentID; |
Table Aliases | SELECT column1,column2,... FROM table1 [alias1], table2 [alias2],... [WHERE condition(s)]; |
SELECT LastName,Points FROM Students S,Assignments A WHERE S.StudentID=A.StudentID AND A.AssignmentID=12; |
Everything | SELECT [DISTINCT] column1 [AS alias1],column2 [AS alias2], ... FROM table1 [alias1], table2 [alias2],... [WHERE condition(s)] [GROUP BY column(s)] [HAVING condition(s)] [ORDER BY column(s) [DESC]]; |
SELECT Points, COUNT(*) AS Cnt FROM Students S,Assignments A WHERE S.StudentID=A.StudentID AND A.AssignmentID=12 GROUP BY Points HAVING Points > 10 ORDER BY Cnt, Points DESC; |
Subquery | SELECT column1, column2 FROM ( SELECT some1 AS column1, some2 AS column2,... FROM table ) AS alias; |
SELECT LastName FROM ( SELECT Books.LastName AS LastName FROM BOOKS GROUP BY LastName ) AS t; |
Official reference of INSERT ... SELECT syntax, UPDATE syntax, DELETE syntax, INSERT syntax, CREATE TABLE syntax and ALTER TABLE syntax.
Click on the What
entry to see the How
's and Examples
's code better formatted.
What | How | Examples |
---|---|---|
Create table | CREATE TABLE table ( column1 type [[NOT] NULL] [AUTO_INCREMENT], column2 type [[NOT] NULL] [AUTO_INCREMENT], ... other options, PRIMARY KEY (column(s)) ); |
CREATE TABLE Students (LastName varchar(30) NOT NULL, FirstName varchar(30) NOT NULL, StudentID int NOT NULL, Major varchar(20), Dorm varchar(20), PRIMARY KEY (StudentID) ); |
Insert data | INSERT INTO table VALUES (list of values); INSERT INTO table SET column1=value1, column2=value2, ... columnk=valuek; INSERT INTO table (column1,column2,...) VALUES (value1,value2...); |
INSERT INTO Students VALUES ('Smith','John',123456789,'Math','Selleck'); INSERT INTO Students SET FirstName='John', LastName='Smith', StudentID=123456789, Major='Math'; |
Insert/Select | INSERT INTO table (column1,column2,...) SELECT statement; |
INSERT INTO Students (StudentID,FirstName,LastName) SELECT StudentID,FirstName,LastName FROM OtherStudentTable WHERE LastName like '%son'; |
Delete data | DELETE FROM table [WHERE condition(s)]; (Omit WHERE to delete all data) |
DELETE FROM Students WHERE LastName like '%Smith%' AND FirstName='John'; |
Updating Data | UPDATE table SET column1=value1, column2=value2, ... columnk=valuek [WHERE condition(s)]; |
UPDATE Students SET LastName='Jones' WHERE StudentID=987654321; |
Insert column | ALTER TABLE table ADD COLUMN column type options; |
ALTER TABLE Students ADD COLUMN Hometown varchar(20); |
Delete column | ALTER TABLE table DROP COLUMN column; |
ALTER TABLE Students DROP COLUMN Dorm; |
Delete table (Careful!) | DROP TABLE [IF EXISTS] table; |
DROP TABLE Animals; |
Official reference of MySQL Column Types.
Purpose | Data Type | Example |
---|---|---|
Integers | int(M) |
int(5) |
Floating-point (real) numbers | float(M,D) |
float(12,3) |
Double-precision | Floating-point |
double(M,D) double(20,3) |
Dates and times | timestamp(M) |
timestamp(8) (for YYYYMMDD) , timestamp(12) (for YYYYMMDDHHMMSS) |
Fixed-length strings | char(M) |
char(10) |
Variable-length strings | varchar(M) |
varchar(20) |
A large amount of text | blob |
blob |
Values chosen from a list | enum('value1',value2',...) |
enum('apples','oranges','bananas') |
What | How | Examples |
---|---|---|
Running MySQL | mysql -uusername -ppassword |
mysql -ucusack2RO -pegbdf5s |
Importing | mysql -uusername -ppassword < filename |
mysql -usomeDB -pblah < myNewDB.sql |
Dumping (Saving) | mysqldump -uusername -ppassword database [tables] > filename |
mysqldump -ume -pblah myDB > My.sql , mysqldump -ume -pblah myDB table1 table2 > my.sql |
Rapid Link to MySQL.com
- MySQL Reference Manual
- MySQL Column Types
- SHOW syntax
- CREATE TABLE syntax
- ALTER TABLE syntax
- INSERT syntax
- DELETE syntax
- UPDATE syntax
- SELECT syntax
- INSERT ... SELECT syntax
- DROP DATABASE
- DROP TABLE
- MySQL Functions
All columns (up ↑)
How (up ↑)
SELECT *
FROM table;
Example (up ↑)
SELECT *
FROM Students;
Some columns (up ↑)
How (up ↑)
SELECT column1,column2,...
FROM table;
Example (up ↑)
SELECT LastName, FirstName
FROM Students;
Some rows/columns (up ↑)
How (up ↑)
SELECT column1,column2,...
FROM table
[WHERE condition(s)];
Example (up ↑)
SELECT LastName,FirstName
FROM Students
WHERE StudentID LIKE '%123%';
No Repeats (up ↑)
How (up ↑)
SELECT [DISTINCT] column(s)
FROM table;
Example (up ↑)
SELECT DISTINCT LastName
FROM Students;
Ordering (up ↑)
How (up ↑)
SELECT column1,column2,...
FROM table
[ORDER BY column(s) [DESC]];
Example (up ↑)
SELECT LastName,FirstName
FROM Students
ORDER BY LastName, FirstName DESC;
Column Aliases (up ↑)
How (up ↑)
SELECT column1 [ AS *alias1*], column2 [ AS alias2], ...
FROM table1;
Example (up ↑)
SELECT LastName,FirstName AS First
FROM Students;
Grouping (up ↑)
How (up ↑)
SELECT column1,column2,...
FROM TABLE
[GROUP BY * COLUMN(s)*];
Example (up ↑)
SELECT LastName, COUNT(*)
FROM Students
GROUP BY LastName;
Group Filtering (up ↑)
How (up ↑)
SELECT column1,column2,...
FROM TABLE [GROUP BY * COLUMN(s)*]
[HAVING CONDITION(s)];
Example (up ↑)
SELECT LastName, COUNT(*)
FROM Students
GROUP BY LastName
HAVING LastName LIKE '%son';
Joins (up ↑)
How (up ↑)
SELECT column1,column2,...
FROM table1,table2,...
[WHERE CONDITION(s)];
Example (up ↑)
SELECT LastName,Points
FROM Students,Assignments
WHERE AssignmentID=12 AND Students.StudentID=Assignments.StudentID;
Table Aliases (up ↑)
How (up ↑)
SELECT column1,column2,...
FROM table1 [alias1], table2 [alias2],...
[WHERE CONDITION(s)];
Example (up ↑)
SELECT LastName,Points
FROM Students S,Assignments A
WHERE S.StudentID=A.StudentID AND A.AssignmentID=12;
Everything (up ↑)
How (up ↑)
SELECT [ DISTINCT] column1 [ AS alias1],column2 [ AS alias2], ...
FROM table1 [alias1], table2 [alias2],...
[WHERE CONDITION(s)]
[GROUP BY COLUMN(s)]
[HAVING CONDITION(s)]
[ORDER BY COLUMN(s) [ DESC]];
Example (up ↑)
SELECT Points, COUNT(*) AS Cnt
FROM Students S,Assignments A
WHERE S.StudentID=A.StudentID AND A.AssignmentID=12
GROUP BY Points
HAVING Points > 10
ORDER BY Cnt, Points DESC;
Subquery (up ↑)
How (up ↑)
SELECT column1, column2
FROM (
SELECT some1 AS column1, some2 AS column2,...
FROM table
) AS alias;
Example (up ↑)
SELECT LastName
FROM (
SELECT Books.LastName AS LastName
FROM Books
GROUP BY LastName
) AS t;
Create table (up ↑)
How (up ↑)
CREATE TABLE TABLE (
column1 TYPE [[ NOT] NULL] [ AUTO_INCREMENT],
column2 TYPE [[ NOT] NULL] [ AUTO_INCREMENT],
... other options,
PRIMARY KEY (COLUMN(s))
);
Example (up ↑)
CREATE TABLE Students (
LastName VARCHAR(30) NOT NULL,
FirstName VARCHAR(30) NOT NULL,
StudentID INT NOT NULL,
Major VARCHAR(20),
Dorm VARCHAR(20),
PRIMARY KEY (StudentID)
);
Insert data (up ↑)
How (up ↑)
INSERT INTO TABLE VALUES (LIST of VALUES);
INSERT INTO TABLE SET column1=value1, column2=value2, ... columnk=valuek;
INSERT INTO TABLE (column1,column2,...) VALUES (value1,value2...);
Example (up ↑)
INSERT INTO Students VALUES ('Smith','John',123456789,'Math','Selleck');
INSERT INTO Students SET FirstName='John', LastName='Smith', StudentID=123456789, Major='Math';
INSERT INTO Students (StudentID,FirstName,LastName) VALUES (123456789,'John','Smith');
Insert/Select (up ↑)
How (up ↑)
INSERT INTO TABLE (column1,column2,...)
SELECT statement;
Example (up ↑)
INSERT INTO Students (StudentID,FirstName,LastName)
SELECT StudentID,FirstName,LastName
FROM OtherStudentTable
WHERE LastName LIKE '%son';
Delete data (up ↑)
How (up ↑)
DELETE FROM table
[WHERE condition(s)];
(Omit WHERE to delete all data)
Example (up ↑)
DELETE
FROM Students
WHERE LastName='Smith';
DELETE
FROM Students
WHERE LastName LIKE '%Smith%' AND FirstName='John';
DELETE
FROM Students;
Updating Data (up ↑)
How (up ↑)
UPDATE TABLE SET column1=value1, column2=value2, ... columnk=valuek
[WHERE CONDITION(s)];
Example (up ↑)
UPDATE Students SET LastName='Jones'
WHERE StudentID=987654321;
UPDATE Students SET LastName='Jones', Major='Theatre'
WHERE StudentID=987654321 OR (MAJOR='Art' AND FirstName='Pete');
Insert column (up ↑)
How (up ↑)
ALTER TABLE table ADD COLUMN column type options;
Example (up ↑)
ALTER TABLE Students ADD COLUMN Hometown varchar(20);
Delete column (up ↑)
How (up ↑)
ALTER TABLE table
DROP COLUMN column;
Example (up ↑)
ALTER TABLE Students
DROP COLUMN Dorm;
Delete table (up ↑)
How (up ↑)
DROP TABLE [IF EXISTS] table;
Example (up ↑)
DROP TABLE Animals;
Partial Code and Examples come from Stephen D. Scott.
Super helpful. Thanks!