Derby - 基本语法

本章为您提供了所有Apache Derby SQL语句的语法。

所有语句均以任何关键字开头，如SELECT，INSERT，UPDATE，DELETE，ALTER，DROP，CREATE，USE，SHOW，而所有语句均以分号(;)结尾。

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Apache Derby的SQL语句区分大小写，包括表名。

CREATE 语句

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 语句

DROP TABLE table_name;

INSERT 语句

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

SELECT 语句

SELECT column_name, column_name, ... FROM table_name;

UPDATE 语句

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

DELETE 语句

DELETE FROM table_name WHERE condition;

DESCRIBE 语句

Describe table_name

TRUNCATE 语句

TRUNCATE TABLE table_name;

ADD COLUMN 添加列

ALTER TABLE table_name ADD COLUMN column_name column_type;

ADD CONSTRAINT 添加约束

ALTER TABLE table_name ADD CONSTRAINT constraint_name constraint (column_name);

DROP COLUMN 删除列

ALTER TABLE table_name DROP COLUMN column_name;

DROP CONSTRAINT 删除约束

ALTER TABLE table_name DROP CONSTRAINT constraint_name;

Where 查询

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 语句

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

ORDER BY 语句

SELECT * FROM table_name ORDER BY column_name ASC|DESC.

HAVING 语句

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

CREATE INDEX 创建索引

CTREATE INDEX index_name on table_name (column_name);

CREATE UNIQUE INDEX 唯一索引

CREATE UNIQUE INDEX index_name on table_name (column_name);

CREATE INDEX 复合索引

CREATE INDEX index_name on table_name (column_name1, column_name2);

SHOW INDEXS 查看索引语句

SHOW INDEXES FROM table_name;

DROP INDEX 删除索引语句

DROP INDEX index_name;