sqlite竖向连接表格

select ... from table_name where condition
union [all]
select ... from table_name where condition

""" union竖向连接表格

union      连接不重复的行
union all  连接重复的行

the statistics of this file:
lines(count)    understand_level(h/m/l)    classes(count)    functions(count)    fields(count)
000000000051    ----------------------l    00000000000000    0000000000000001    ~~~~~~~~~~~~~
"""

import time
import sqlite3

__author__ = '与C同行'


def print_pretty_outcome(cursor):
    print('-' * 80)
    all_outcome = cursor.fetchall()
    for column_desc in cursor.description:
        print(f'{column_desc[0]:<20}', end='')
    print()
    for item in all_outcome:
        for cell in item:
            try:
                print(f'{cell:<20}', end='')
            except TypeError:
                cell = 'None'
                print(f'{cell:<20}', end='')
        print()
    print('-' * 80)
    print()


if __name__ == '__main__':
    print(f'当前时间:{time.ctime()}')
    conn = sqlite3.connect('learn.db')
    c = conn.cursor()

    print()
    print('union连接多个表格,不重复相同行')
    c.execute('select name from report_tb union select name from salary_tb')
    print_pretty_outcome(c)

    print('union all连接多个表格,重复相同行')
    c.execute('select name from report_tb' 
              ' union all select name from salary_tb')
    print_pretty_outcome(c)

    c.close()
    conn.close()

从上面的结果中可以清晰地看到使用uinon
和union all
的区别。