SQLite basis -5. Data Manipulation Language

An added data (insert)

INSERT INTO is used to add data to a table in the database.

-- 语法 1
INSERT INTO table_name (column1, column2, ... ,columnN)
            VALUES (value1, value2, ... , valueN);
-- 语法 2 
-- 当为表里所有列添加数据时，可以省略列名。但值要与列名顺序一致。
INSERT INTO table_name
            VALUES (value1, value2, ... , valueN);

-- 实例
INSERT INTO link_men
            VALUES ('eric', '1991-12-19', '深圳市', 999.99);

An import data from another table

-- 语法
INSERT INTO table_ame_1
    SELECT column1, ... , columnN
    FROM table_name_2
    WHERE [condition]; 

-- 实例
-- 创建 新表 link_men_1
create table link_men_1 (
    id int primary key,
    name text not null,
    salary real
)

-- 从link_men表中导入id、姓名、工资
insert into link_men_1
    select id, name, salary
    from link_men
    where 1=1;

Second, the query data (select)

SELECT can obtain data from the database and returns the result in table form.

-- 语法

SELECT * FROM table_name
WHERE [condition]; -- 返回所有字段
SELECT column1 FROM table_name
WHERE [condition]; -- 仅返回column1字段

-- 实例
select * link_men
-- 如果不加条件，则查询表中所有数据。
where id = 1;

Third, the update data (update)

UPDATE for modified data existing in the table.

-- 语法
UPDATE table_name
SET column1 = value1, ... , columnN = valueN
WHERE [condition];

-- 实例
update link_men
set salary = 888.88
-- 如果不加条件，则更新表中所有数据的salary值。
where id = 1;

Third, delete data (delete)

DELETE for deleting the existing data in the table.

-- 语法
DELETE FROM table_name
WHERE [condition];

-- 实例
delete from link_men
-- 如果不加条件，则删除表中的所有数据。
where id = 1;