Question

我想为它创建一个DB表和一组命令。所以目前我有

this->command_create_files_table = "CREATE TABLE IF NOT EXISTS files (encoded_url varchar(300) UNIQUE NOT NULL primary key, file_name varchar(150) NOT NULL, user_name varchar(65) NOT NULL, is_public BOOLEAN NOT NULL, modified DATETIME NOT NULL default CURRENT_TIMESTAMP )";
this->command_create_file = "INSERT INTO files (encoded_url, file_name, user_name, is_public ) VALUES (:encoded_url, :file_name, :user_name, :is_public)";
this->command_update_file = " UPDATE files SET encoded_url=:new_encoded_url, file_name=:new_file_name, is_public=:is_public, modified=CURRENT_TIMESTAMP  WHERE encoded_url=:encoded_url";
this->command_delete_file = "DELETE FROM files WHERE encoded_url=:encoded_url";
this->command_find_file = "SELECT file_name, user_name, is_public, modified FROM files WHERE encoded_url=:encoded_url";
this->command_find_all_user_files = "SELECT encoded_url, file_name, user_name, is_public, modified FROM files WHERE user_name=:user_name";

（在此处使用sqlite3pp语法）

我想知道如何SELECT某些预定义的:N（例如25个 - 不多）文件或更少的文件来自某个起点DATETIME点（例如CURRENT_TIMESTAMP）？< / p>

Answer 1

SELECT 
    fields_you_want_to_select
FROM 
    filesTbl
WHERE 
    DATETIME > start_of_range AND
    DATETIME < end_of_range
LIMIT limit_num

Answer 2

SELECT 
    fields_you_want_to_select
FROM 
    filesTbl
WHERE 
    DATETIME > start_of_range AND
    DATETIME < end_of_range
LIMIT
    25

SQLite：如何选择一系列记录？

2 个答案: