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beandog
Bodhisattva
Joined: 04 May 2003
Posts: 2066
Location: /usa/utah
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 Posted: Sat Oct 16, 2004 4:45 pm Post subject: [Mini-Doc] SQL Cheatsheet |
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[Mini-Doc] SQL Cheatsheet
Be warned: This is by no means a complete or very cleaned up list -- its mostly just a formatted dump of my notes I've been taking. I would like to clean it up though as I go along.
I originally wanted to have the queries for SQLite included as well, but they usually almost identical to every command PostgreSQL uses.
Show databases, tables, table description, indexes
MySQL
| Code: | show databases;
show tables;
desc table_name;
SHOW INDEX FROM table_name; |
PostgreSQL
| Code: | \l
\dt
\d table_name
\d table_name |
Create new table from a SELECT statement
MySQL
| Code: | | CREATE TABLE new_table SELECT * FROM old_table; |
PostgreSQL
| Code: | | CREATE TABLE new_table AS SELECT * FROM old_table; |
Create an index
PostgreSQL
Note that with postgres, an index has a unique name across that db. You can't have two indexes named "id", even though they are on different tables. However, it does make for managing them a bit easier (imo).
| Code: | | CREATE [UNIQUE] INDEX index_name ON table_name (column1); |
Delete an index
MySQL
| Code: | | ALTER TABLE table_name DROP INDEX index_name; # I think -- pulled this one from memory |
PostgreSQL
| Code: | | DELETE INDEX index_name; |
Rename table
MySQL
| Code: | | ALTER TABLE table_name RENAME TO new_table_name; |
PostgreSQL
| Code: | | ALTER TABLE table_name RENAME new_table_name; |
Replace text
MySQL
| Code: | | UPDATE table_name SET column_name = REPLACE(column_name, 'old', 'new'); |
PostgreSQL
| Code: | | UPDATE table_name SET column_name = REPLACE(column_name, 'old', 'new'); |
Rename column
MySQL
| Code: | | ALTER TABLE table_name CHANGE column_old column_new (type); |
Add a new column
MySQL
| Code: | | ALTER TABLE table_name ADD COLUMN new_column (type) [not null [FIRST|AFTER column]]; |
Add a primary key
MySQL
| Code: | | ALTER TABLE table_name ADD PRIMARY KEY(column_name); |
Add autoincrement
MySQL
| Code: | ALTER TABLE tablename ADD PRIMARY KEY(column);
ALTER TABLE table_name CHANGE column_name column_name int unsigned auto_increment; |
Empty table, reset autoincrement value
MySQL
| Code: | | TRUNCATE table_name; |
PostgreSQL
| Code: | | TRUNCATE table_name; |
Dump tables
MySQL
| Code: | | # mysqldump database_name --tables table1 table2 table3 |
PostgreSQL
| Code: | # pg_dump database_name # all tables
#pg_dump --table=table_name # one table |
SQLite-compatible database dump
PostgreSQL
| Code: | | pg_dump -t tablename -a -f table.sql -O -x -d database |
Set some environment variables
MySQL
| Code: | # vim ~/.my.cnf
[client]
host=localhost # where to connect
password # always prompt for password
user=steve # mysql username
database=gentoo_org # database name
pager=/usr/bin/less # pager to use
port=3306 # port to connect to mysql on
# see mysql --help for more variables |
PostgreSQL - see http://www.postgresql.org/docs/current/static/libpq-envars.html
| Code: | # vim ~/.bashrc
export PGDATABASE="gentoo_org"
export PGUSER="steve" |
Edit a query with $EDITOR
PostgreSQL
Create a new user
PostgreSQL
| Code: | CREATE USER 'steve' WITH PASSWORD 'password';
CREATE USER 'steve' WITH PASSWORD 'password' CREATEUSER; # add create user privileges
CREATE USER 'steve' WITH PASSWORD 'password' CREATEDB; # add create database privileges
CREATE USER 'steve' WITH PASSWORD 'password' CREATEUSER CREATEDB; # add both |
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