Update statements associated with multiple tables in MSSQL
For example, table A has the following fields:Aid A1 A2 A3 A4Fields in Table B:Bid B1 B2 B3 B4
If you use all fields in Table B to update the corresponding fields in Table A, you can write the following in ms SQL Server:UpdateSet a1 = B. B1, a2 = B. B2, A3 =
This article mainly introduces how to update and delete multiple objects in Django. Django is the most popular among Python frameworks. For more information, see
Update multiple objects
For example, we want to change the name of Apress Publisher from "Apress" to "Apress Publishing ". If you use the save () method, for
The update in SQL implements Multi-Table update during development, and the database is switched back and forth, and some key syntaxes are different. This is a headache for developers. this article summarizes the usage of the Update statement in three databases: SQLServer, Oracle, and MySQL when updating
" this option, what is the use of this option? Computed column If there is no special setting, it will be a virtual column, that is, the column actually does not exist, but each time you want to take the value of this column, SQL will be calculated by the formula of the computed column once, and then return the results to us. There are problems, for example, that each calculation consumes a certain amount of time, and you cannot create an index on tha
Mysql update modifies multiple data entries and mysql updatesGenerally, the following SQL statement is used to update the field value:Copy codeThe Code is as follows:UPDATE mytable SET myfield = 'value' WHERE other_field = 'other _ value ';However, what if you want to update
be accomplished with a little bit of skill.
Copy Code code as follows:
UPDATE mytable
SET myfield = case ID
When 1 THEN ' value '
When 2 THEN ' value '
When 3 THEN ' value '
End
WHERE ID in (1,2,3)
This is a small trick to implement batch updates using the case.As an example:
Copy Code code as follows:
UPDATE Categories
SET Display_order = case ID
WHERE Other_field (' other_values ')
If the Where condition query out the ID of the record is not within the case range, MyField will be set to null.
If you update multiple values, you need to modify them only slightly:
UPDATE mytable
SET myfield1 = case ID if
1 THEN ' Myvalue11 ' when
2 THEN ' Myvalue12 ' when
3 THEN ' Myva Lue13 ' End
,
myf
Label:MySQL statement: Batch update of different values for multiple records MySQL UPDATE statement is simple, update a field of the data, generally write:
1
UPDATEmytable SETmyfield = ‘value‘WHERE other_field = ‘other_value‘;
If you update
Because Oracle does not support the update or delete from statement, Oracle's Multiple Table association update and delete must be supported by subqueries, and, similarly, Oracle does not support simultaneous update or delete multiple tables, typically using the following:
How can I locate multiple mysql tables in which the content is sorted by the last update time? how can I locate multiple mysql tables in which the content is sorted by the last update time?
The four fields are the same, and only the content is different.
Table name: aaa, bbb, ccc, and ddd
Table fields: title, classid
SQL statement: Way One
Copy Code code as follows:
Public list{
Use using a flexible and convenient, use the con without manual shutdown, will automatically close the current connection
Using (SqlConnection con=new SqlConnection (Constr))
{
Open connection
Con. Open ();
String cmdstr = "SELECT * from Ns_user where userid= @myid and username= @myname";
SqlCommand cmd = new SqlCommand (Cmdstr,con);
This uses parameter serialization
when 3 Then 5 ENDWHEREIdinch(1,2,3)This SQL means, update the Display_order field, if id=1 the value of Display_order is 3, if id=2 Display_order value is 4, if id=3 then Display_order value is 5. That is, the conditional statements are written together. The where section here does not affect the execution of the code, but it improves the efficiency of SQL
Tags: mysql optimized storageTypically, we use the following SQL statement to update field values:Copy CodeThe code is as follows:UPDATE mytable SET myfield= ' value ' WHERE other_field= ' other_value ';But what do you do if you want to update multiple rows of data, and each field value is different for each row of rec
Translate Part 4: Updating our Database of ScottGu about LINQ to SQL. This Post explains how to update a database using LINQ to SQL, and how to integrate the business logic and custom verification logic. The development environment is. NET Framework 3.5 Beta2 and the development tool is Visual Studio 2008 Beta2.
Use LINQ to S
Tags: parse SSO research target category SDN condition development Query in the process of reporting for the Bureau of Personnel, encountered a thorny problem. Customer requests that a column of data in a database be divided into multiple columns according to the criteria. For example, there are provinces in the database that have such a column of data Customer requirements are categorized according to th
Implementation Code of SQL update multi-table join update, sqlupdate
Update multiple tables, especially the data in Table A and Table B of table A. The following is an example.
There are tables A and B with the following records:
Table
C1 c2--------------1 a12 a23 a38 a8
Tab
I tried multiple times and finally concluded that when multiple SQL Server tables are associated with update, an as Alias cannot be added to an external table, and a syntax error is returned.Only the table name can be written as the prefix for reference and cannot be referenced using an alias.The syntax can be referred
SQL is required. Note chapter 16th to update and insert data. SQL is required.16.1 update data
To UPDATE (modify) The data in the table, you can use the UPDATE statement. UPDATE can be
Label:The MySQL UPDATE statement is simple, updating one field of multiple data with the same value, which is generally the case: UPDATE table_name SET field = ' value ' WHERE condition; To update multiple data to different values, you can: foreach ($display _order as $id
Oracle Multiple Table Association UPDATE statement
1 The simplest form of SQL code
--confirmed that all customer_id less than 1000 of the Customers table are ' Beijing '
Within the--1000 are the company to the country before the old customers in the city:
Update customers
set city_name= ' Beijing '
where customer_id1
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