now there are two tables, as shown in the figure the question is: how do I write a sql statement to query the data that contains a field (user_id) in Table 2 (m_top_user_list)? Thank you ~ ...
LinqToSql database query method is: first create a dbml file, and then drag the tables in the database you need directly into the dbml editing interface. Like this: when dragged in like this, the entity classes corresponding to these tables are aut...
mysql version 5.7 question 1: add an index to a field of numeric type: if the date is stored as int, can you add an index to the date in such a way as index or key? index (field name)? question 2: whether to use index or key to index the plastic ...
id name relation 1 n1 r1 2 n2 r2 3 n4 r1 4 n5 r1 5 n6 r2 6 n6 r1 the relation relationship of the table is shown above where the relation field indicates the relationship between the cur...
isolation level and lock appearance seem to solve the problems caused by database transaction concurrency, right? What s the relationship between the two? I m a little confused ...
as the title, my question is, for example, there is a table with five pieces of data in it, respectively * 1 * { "_id" : ObjectId("5b50807f334ca1071be530aa"), "a" : , "a" : 2 } * 2 * { "...
the storage engine for rental tables is innodb, rental_ myisam tables, and the storage engine for Myisam tables is myisam. The structure of the two tables is the same except for different storage engines. CREATE TABLE `rental` ( `rental_id` int(11) N...
I want to output a comma-separated string 1 br 2 3 4 5 as select "1,2,3,4,5 " ...
query the student numbers and names of students who have studied "001 " and also learned the course number "002 "; select student.sid,student.sname from student,sc where student.sid=sc.sid and sc.cid=1 and exists (select * from sc as sc_2 where sc....
SELECT DISTINCT GROUP_CONCAT( DISTINCT pch.erpContractNumber ) AS fbk22, poh.*, IFNULL(eei.shortName, eei.fullName) AS companyShortName, GROUP_CONCAT(DISTINCT poi.fbk7) AS materialNumber FROM purchase_order_header poh LEFT JOIN...
SQLAdvisor ends! Error log: Invalid parameter number ...
The database has a doneNum field that represents the number of completions. It was originally designed as varchar (38) with this schedule in mind. doneNum sum(doneNum) I would like to ask you, is there any other solution? ...
deal with the problem that Wechat users bind mobile numbers and mobile phone numbers bind Wechat now the tricky thing is that Wechat users and mobile phone number users are in two tables. what s more tricky is that Wechat users and mobile phone numb...
sql: select * from employees s where not exists (select 1 from dept_emp d where d.emp_no=s.emp_no) Inner table s: exterior d: explanation of exists on the Internet: exists is an external table as a loop loop, and each loop cycle queries the inner ...
:HTTPS: HEALTH.123.COM 456.HTML :HTTPS: NEWS.123.COM 789.HTML :HTTPS: HEALTH.123.COM 147.HTML .... SQL HEALTH456 :MSSQL2014 :`update [newdata].[dbo].[Article] set Content=Replace(Upper(Cast(Content as nvarchar(max))), , )` ...
how to design a database of classified information? I want to write all the main contents of the information (title,content) in an info table. I don t know how to design the table for special properties. category table-Real Estate Job Category in...
there is no problem for the database to insert data using Mysql, insert, but I don t know why the update data has not been updated successfully. The mysql update statement is as follows: UPDATE `system_member` SET `passwd`= e968053af15baf1b6f52458bb...
{ string strConnection = "Server=DESKTOP-TH8QSR9;"; strConnection += "initial catalog=test;"; strConnection += "user id=DESKTOP-TH8QSR9 suchao;"; strConnection += "password=;"...
when querying SQL, you need to process the data to find the difference. Some units are hours, times, and seconds. For example, when an hour subtracts seconds, the second should be converted to an hour with a difference less than a certain value to send m...
select regexp_replace (regexp_replace) Yu 0min Za , , ), [ u4e00 - u9fa5. The running result of ORACLE ORACLE] {1,} , U4e00 - u9fa5. The result of Yu Minli GP running:?? The result of HIVE running in Yu 0 min Za:? 0Za Why are the res...
description: mobile web uses vue to implement the left and right column layout. The left side is a list of various information table names, and the right side is the content that is loaded dynamically after clicking the left menu. The content on the rig...
laravel time query error Controller: ::: ...
def f (x): return (10merx) a = [1Jing 2jue 3] b = [f (t) for t in a] print (b) result: the meaning of [10,20,30] is understandable, but I want to know how the compiler breaks down the sentence b = [f (t) for t in a] into step-by-step commands? It...
problem description I want to copy the following code into wps wps: mysql> show tables from employees; +----------------------+ | Tables_in_employees | +----------------------+ | current_dept_emp | | departments | | dept_emp ...
want to achieve an effect page is empty Click the + sign plus DIV, then click on any of these generated div, how to pop up the subscript? attach my code: < html lang= "en " > < head > <meta charset="UTF-8"> <title>Title&l...