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Essential MySQL Cheat Sheet

Posted on by Anonymous Guest 3 minutes read

I have googled the same queries related to SQL numerous times. There are plenty of MySQL cheat sheets available, but each seems to be missing something. I have tried to collect all of them in a single cheat sheet that fulfills my needs. If something is missing, do not hesitate to mention it via comments below. Happy SQLing !!!

 

MySQL Data Types
CHARString (0 – 255)
VARCHARString (0 – 255)
TINYTEXTString (0 – 255)
TEXTString (0 – 65535)
BLOBString (0 – 65535)
MEDIUMTEXTString (0 – 16777215)
MEDIUMBLOBString (0 – 16777215)
LONGTEXTString (0 – 429496­7295)
LONGBLOBString (0 – 429496­7295)
TINYINT xInteger (-128 to 127)
SMALLINT xInteger (-32768 to 32767)
MEDIUMINT xInteger (-8388608 to 8388607)
INT xInteger (-2147­483648 to 214748­3647)
BIGINT xInteger (-9223­372­036­854­775808 to 922337­203­685­477­5807)
FLOATDecimal (precise to 23 digits)
DOUBLEDecimal (24 to 53 digits)
DECIMAL“­DOU­BLE­” stored as string
DATEYYYY-MM-DD
DATETIMEYYYY-MM-DD HH:MM:SS
TIMESTAMPYYYYMM­DDH­HMMSS
TIMEHH:MM:SS
ENUMOne of preset options
SETSelection of preset options

 

Select queries
select all columns SELECT * FROM tbl;
select some columns SELECT col1, col2 FROM tbl;
select only unique records SELECT DISTINCT FROM tbl WHERE condition;
column alias with AS SELECT col FROM tbl AS newname;
order results SELECT * FROM tbl ORDER BY col [ASC | DESC];
group results SELECT col1, SUM(col2) FROM tbl GROUP BY col1;

 

Creating and modifying
create a database CREATE DATABASE db_name;
select a database USE db_name;
list the databases on the server SHOW DATABASES;
show a table’s fields DESCRIBE tbl;
create a new table CREATE TABLE tbl (field1, field2);
insert data into a table INSERT INTO tbl VALUES (“va­l1”, “­val­2”);
delete a row DELETE * FROM tbl WHERE condition;
add a column from a table ALTER TABLE tbl ADD COLUMN col;
remove a column from a table ALTER TABLE tbl DROP COLUMN col;
make a column a primary key ALTER TABLE tbl ADD PRIMARY KEY (col);
return only 1 row matching query … LIMIT = 1
amend the values of a column UPDATE table SET column­1=”v­al1­” WHERE …
clear all the values, leaving the table structure TRUNCATE TABLE tbl;
delete the table DROP TABLE tbl;
delete the database DROP DATABASE db_name;

 

Matching data
matching data using LIKE SELECT * FROM tbl1 WHERE col LIKE ‘%value%’
matching data using REGEX SELECT * FROM tbl1 WHERE col RLIKE ‘regul­ar_­exp­res­sion’

 

Joins
INNER JOINreturns only where match in both tables
OUTER JOINalso returns non-ma­tching records from both tables
LEFT JOINalso returns non-ma­tching records from left table
RIGHT JOINalso returns non-ma­tching records in right table

Integers (marked x) that are “­UNS­IGN­ED” have the same range of values but start from 0 (i.e., an UNSIGNED TINYINT can have any value from 0 to 255).

JOIN syntax:SELECT * FROM tbl1 INNER JOIN tbl2 ON tbl1.id = tbl2.id;

 

String functions mySQL
Compare stringsSTRCMP­(“st­r1″,­”­str­2”)
Convert to lower caseLOWER(­”­str­”)
Convert to upper caseUPPER(­”­str­”)
Left trimLTRIM(­”­str­”)
Substring of a stringSUBSTR­ING­(“st­r”,”i­nx1­”­,”in­x2″)
Concat­enateCONCAT­(“st­r1″,­”­str­2”)

 

MySQL calcul­ation functions
Count rowsCOUNT(col)
AverageAVG(col)
Minimum valueMIN(col)
Maximum valueMAX(col)
Sum of valuesSUM(col)
MySQL Cheat Sheet

Anonymous Guest

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