Registro de operaciones diarias de MySQL

1. Verifique la versión de MySQL

select version();

2. Copie rápidamente la estructura de la tabla, excluyendo las claves primarias y restricciones relacionadas.

create table user_test as select * from user where 1=2;

3.uuido

select uuid(),uuid_short();

4. Reemplace '-' en uuid() con ''

select replace(uuid(),'-','');

5. resumen md5

select md5(uuid()),md5('123456');

6. Copiar datos

insert into user_test(id, name, age, city) 
select replace(uuid(),'-',''),name,age,'vue3' from user;

insert into user_test(id, name, age, city) 
select md5(uuid()),name,25,city from user;

7.Dirección IP4 a número entero, número entero a dirección ip4

select INET_ATON('127.0.0.1') address_2_number,
INET_NTOA(2130706433) number_2_address;

8. Eliminar datos. No se permite eliminar/actualizar durante la consulta.

delete from user_test where id in (select id from user_test where parent_id='75e2f86d0a2c11ee89c70242ac110002');
-- [HYO00][1093] You can't specify target table 'user_test' for update in FROM clause
delete from user_test where id in (select id from (select id from user_test where parent_id='75e2f86d0a2c11ee89c70242ac110002') t);

9. Consultar el campo blob de la base de datos.

select convert(remark using utf8) from user

10. Consulta de correlación, las estadísticas sin datos son 0, construye datos básicos, implementa subconsulta o consulta de conexión

select l.province,ifnull(
    (select biz.num from (
        select '北京' as province,100 as num
        union all
        select '深圳' as province,208 as num
    ) biz where biz.province = l.province),0) as num
from (select '北京' as province
      union all
      select '上海'
      union all
      select '广州'
      union all
      select '深圳') l