Apache Derby 简明教程

Apache Derby - Syntax

此章节为您提供所有 Apache Derby SQL 语句的语法。

所有语句均以任何关键字（如 SELECT、INSERT、UPDATE、DELETE、ALTER、DROP、CREATE、USE、SHOW 等）开始，所有语句均以分号 (;) 结束。

Apache Derby 的 SQL 语句大小写敏感，包括表名。

CREATE Statement

CREATE TABLE table_name (
   column_name1 column_data_type1 constraint (optional),
   column_name2 column_data_type2 constraint (optional),
   column_name3 column_data_type3 constraint (optional)
);

DROP TABLE

DROP TABLE table_name;

INSERT Statement

INSERT INTO table_name VALUES (column_name1, column_name2, ...);

SELECT Statement

SELECT column_name, column_name, ... FROM table_name;

UPDATE Statement

UPDATE table_name
   SET column_name = value, column_name = value, ...
   WHERE conditions;

DELETE Statement

DELETE FROM table_name WHERE condition;

DESCRIBE Statement

Describe table_name

SQL TRUNCATE TABLE Statement

TRUNCATE TABLE table_name;

ALTER Statement – Adding column

ALTER TABLE table_name ADD COLUMN column_name column_type;

ALTER Statement – Adding constraint

ALTER TABLE table_name ADD CONSTRAINT constraint_name constraint (column_name);

ALTER Statement – Dropping column

ALTER TABLE table_name DROP COLUMN column_name;

ALTER Statement – Dropping constraint

ALTER TABLE table_name DROP CONSTRAINT constraint_name;

WHERE Clause

SELECT * from table_name WHERE condition;
or,
DELETE from table_name WHERE condition;
or,
UPDATE table_name SET column_name = value WHERE condition;

GROUP BY Clause

SELECT column1, column2, . . . table_name GROUP BY column1, column2, . . .;

ORDER BY Clause

SELECT * FROM table_name ORDER BY column_name ASC|DESC.

Having Clause

SELECT column1, column2 . . . from table_name GROUP BY column having
condition;

Creating Index

CTREATE INDEX index_name on table_name (column_name);

Creating an UNIQUE index

CREATE UNIQUE INDEX index_name on table_name (column_name);

Creating a COMPOSITE index

CREATE INDEX index_name on table_name (column_name1, column_name2);

Displaying the Indexes

SHOW INDEXES FROM table_name;

Dropping Indexes

DROP INDEX index_name;