# SQL 快速参考 **来自 W3School 的 SQL 快速参考。可以打印它，以备日常使用。** ## SQL 语句 | 语句 | 语法 | | --- | --- | | AND / OR | SELECT column_name(s) FROM table_name WHERE condition AND|OR condition | | ALTER TABLE (add column) | ALTER TABLE table_name ADD column_name datatype | | ALTER TABLE (drop column) | ALTER TABLE table_name DROP COLUMN column_name | | AS (alias for column) | SELECT column_name AS column_alias FROM table_name | | AS (alias for table) | SELECT column_name FROM table_name  AS table_alias | | BETWEEN | SELECT column_name(s) FROM table_name WHERE column_name BETWEEN value1 AND value2 | | CREATE DATABASE | CREATE DATABASE database_name | | CREATE INDEX | CREATE INDEX index_name ON table_name (column_name) | | CREATE TABLE | CREATE TABLE table_name ( column_name1 data_type, column_name2 data_type, ....... ) | | CREATE UNIQUE INDEX | CREATE UNIQUE INDEX index_name ON table_name (column_name) | | CREATE VIEW | CREATE VIEW view_name AS SELECT column_name(s) FROM table_name WHERE condition | | DELETE FROM | DELETE FROM table_name (**Note:** Deletes the entire table!!) _or_ DELETE FROM table_name WHERE condition | | DROP DATABASE | DROP DATABASE database_name | | DROP INDEX | DROP INDEX table_name.index_name | | DROP TABLE | DROP TABLE table_name | | GROUP BY | SELECT column_name1,SUM(column_name2) FROM table_name GROUP BY column_name1 | | HAVING | SELECT column_name1,SUM(column_name2) FROM table_name GROUP BY column_name1 HAVING SUM(column_name2) condition value | | IN | SELECT column_name(s) FROM table_name WHERE column_name IN (value1,value2,..) | | INSERT INTO | INSERT INTO table_name VALUES (value1, value2,....) _or_ INSERT INTO table_name (column_name1, column_name2,...) VALUES (value1, value2,....) | | LIKE | SELECT column_name(s) FROM table_name WHERE column_name LIKE pattern | | ORDER BY | SELECT column_name(s) FROM table_name ORDER BY column_name [ASC|DESC] | | SELECT | SELECT column_name(s) FROM table_name | | SELECT \* | SELECT \* FROM table_name | | SELECT DISTINCT | SELECT DISTINCT column_name(s) FROM table_name | | SELECT INTO (used to create backup copies of tables) | SELECT * INTO new_table_name FROM original_table_name _or_ SELECT column_name(s) INTO new_table_name FROM original_table_name | | TRUNCATE TABLE (deletes only the data inside the table) | TRUNCATE TABLE table_name | | UPDATE | UPDATE table_name SET column_name=new_value [, column_name=new_value] WHERE column_name=some_value | | WHERE | SELECT column_name(s) FROM table_name WHERE condition |