Derby 语法
本章为您提供了所有 Apache Derby SQL 语句的语法。
所有语句都以任何关键字开头，例如 SELECT、INSERT、UPDATE、DELETE、ALTER、DROP、CREATE、USE、SHOW，并且所有语句都以分号 (;) 结尾。
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)
);
删除表
INSERT 语句
INSERT INTO table_name VALUES (column_name1, column_name2, ...);
SELECT 语句
SELECT column_name, column_name, ... FROM table_name;
更新声明
UPDATE table_name
SET column_name = value, column_name = value, ...
WHERE conditions;
删除语句
DELETE FROM table_name WHERE condition;
DESCRIBE 声明
SQL TRUNCATE TABLE 语句
TRUNCATE TABLE table_name;
ALTER 语句-添加列
ALTER TABLE table_name ADD COLUMN column_name column_type;
ALTER 语句-添加约束
ALTER TABLE table_name ADD CONSTRAint constraint_name constraint (column_name);
ALTER 语句 – 删除列
ALTER TABLE table_name DROP COLUMN column_name;
ALTER 语句 – 删除约束
ALTER TABLE table_name DROP CONSTRAint constraint_name;
WHERE 子句
SELECT * from table_name WHERE condition;
or,
DELETE from table_name WHERE condition;
or,
UPDATE table_name SET column_name = value WHERE condition;
按条款分组
SELECT column1, column2, . . . table_name GROUP BY column1, column2, . . .;
按条款排序
SELECT * FROM table_name ORDER BY column_name ASC|DESC.
有条款
SELECT column1, column2 . . . from table_name GROUP BY column having
condition;
创建索引
CTREATE INDEX index_name on table_name (column_name);
创建唯一索引
CREATE UNIQUE INDEX index_name on table_name (column_name);
创建复合索引
CREATE INDEX index_name on table_name (column_name1, column_name2);
显示索引
SHOW INDEXES FROM table_name;
删除索引
