mysql update multiple columns

Tags: select databaseUpdate Dept B, (select Group_concat (T.deptid), Group_concat (d.deptname separator '/') as Dname, T.id, t.deptname from (sel ECT Substring_index (Substring_index (A.deptid, ', ', b.help_topic_id+1), ', ', -1) as DeptID, a.ID, A.deptname from (select D.father as DeptID, D.id, D.deptname from Dept D) a join Mysql.help_topic B on b.help_topic_id GROUP by ID, deptname) C set b.location=c.dname where b.id = C.idEffectCopyright NOTICE: This article for Bo Master original article,

Label:DemandThe following two tables student (student table), score (Test score table)Statistics are required: After 2015-03-10, the scores of the test scores of the sex age=1 were divided into the average.Requirement: Use a SQL Statistics score table to update the results to the Score_sum and Score_avg fields of the student table.ResultsRealize:If we only need to update a field,

deletion operations to prevent accidental deletion. Ii. Transaction Processing for data table operations, it is obvious that queries are more secure than update operations, because update operations may encounter errors, as a result, the update operation is not completed correctly according to the established requirements. However, in many cases,

such as an error in the Oracle database:CREATE TABLE Db_meta_web.user (ID varchar2 (255 char) NOT NULL, account VARCHAR2 (255 char), Department VARCHAR2 (255 Char), Email varchar2 (255 char), mobile varchar2 (255 char), name VARCHAR2 (255 char), password varchar2 (255 char), PRIMARY key (ID ))The table name user and field name password fields Here are reserved keywords, so the error identifier is invalid.In this case, you need to put the DDL statement in the Database Connection tool, with the co

rammer) [1002] = = Array ([id] = 1002 [Name] = Terry [age] = > [profEssion] = designer) [1003] = = Array ([id] = 1003 [name] + Alex [Age] = [profession] = Tester) do not specify a return column, do not specify an index column array ([0] = = Array ( [id] = 1001 [name] + fdipzone [age] [[profession] = Programmer ) [1] = = Array ([id] = 1002 [Name] = Terry [age] + 19 [Profession] = designer) [2] = = Array ([id] = 1003 [name] =G T Alex [age] [profession] = tester)) This

Label:In writing SQL, we often encounter such a problem. Every time you insert, you have to judge whether the data table already exists in this data, the so-called same data, except the primary key all columns are the same, no insert, there is update. In this situation, we do not know whether this column exists, so the simple insertion and update are problematic,

In MySQL:[SQL] Viewplaincopyprint?--single-row stitching, first find a row, plus a comma, and then the next line of stitching isolatedSelectGroup_concat (E.support) fromENGINES EwhereE.xainch('YES','NO') --The results are as follows: Yes,yes,yes,yes,yes,yes,default,yes --replace the "," in the result of the query with the "* *" numberSelect REPLACE(Group_concat (E.support),',','**') fromENGINES EwhereE.xainch('YES','NO') --The results are as fo

MyBatis is recognized and used by everyone because of its simplicity and ease of use. But in the batch update operation, the online introduction of seemingly incomplete, just do a record today, we progress together In the actual project development process, there is often such a requirement: According to the IDs update the table of a field value, the SQL statement is: Public interface Istaffdao { void Bat

The following article mainly introduces the actual usage of the MySQL update statement. We first use the UPDATE statement of a single table to introduce the actual solution for implementing the MySQL update statement. The following is the detailed description of the article,

Does MySql Delete and update operations affect performance? mysql Delete and update Performance The cost of Delete and update operations is usually higher than that of insert operations. Therefore, a good design requires less database up