(My)SQL Cheat Sheet

Here are the most commonly used SQL commands and the most commonly used options for each. There are many more commands and options than listed here. In other words, the syntaxes as I have listed them are far from complete. See the links at the bottom for more complete syntaxes and more commands.

MySQL Command-Line
What How Example(s)
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
Common 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’)

M is maximum to display, and D is precision to the right of the decimal.
MySQL Mathematical Functions
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)
MySQL String Functions
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)
Basic MySQL Commands
What How Example(s)
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;
SQL Commands: Modifying
What How Example(s)
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 INTO Students
(StudentID,FirstName,LastName)
VALUES (123456789,’John’,’Smith’);
Insert/Select INSERT INTO table (column1,column2,…)
SELECT statement;
(See below)
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=’Smith’;
DELETE FROM Students
WHERE LastName like ‘%Smith%’;
AND FirstName=’John’;
DELETE FROM Students;
Updating Data UPDATE table SET
column1=value1,
column2=value2,

columnk=valuek
[WHERE condition(s)];
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 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;
SQL Commands: Querying
What How Example(s)
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;

For more details, see the following pages from MySQL.com.

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