update column from another table sql

Label:MySQL cross-table update has always been the topic of concern, this article describes the MySQL Multi-table update in the practice of several different ways of writing, the need for a friend can refer to the assumption that we have two tables, a table for the Product

After reading the article, it is very enlightening that MySQL is usually the first select when it is update, and at this point, if the index is not used, it will lock the entire table. The best use of indexesBy using the primary key, if we know the scope of the primary key (as long as it is a superset of the exact range), you can add the scope of the primary key in the query condition so that the queryBy us

If you have entered this post, then you must have encountered the same problem as me. Do not look at the set case of the topic when ..., I started with the first reaction is to use case when but found not to work.It's a little bit bigger than that: dynamic specifies the field to modify.In fact, little white here did not find the solution I thought [laughter cry], but at least the problem is solved.Here are the addresses of the original posts:Http://stackoverflow.com/questions/4830191/t-

Tags: io for ar art CTI on EF C SQLIn SQL Server, trigger, INSERT, UPDATE, delete state:CREATE TRIGGER t_inms_alarmsOn [PHS]. [dbo]. [Alarmcurrent]For INSERT, DELETEAsDECLARE @rows intSELECT @rows = @ @rowcountIF @rows = 0Return--If the table is inserted, synchronize the update alarmsmiddletblIF EXISTS (select 1 from i

Yesterday found in the program data analysis results are not, after the analysis, the original data is still, the value of the field is cumulative. Heart said, not Ah, is to regenerate records before the analysis of AH. Did you forget to delete it? Check the code, found that there are DELETE statements. Then execute in Query Analyzer, error. Try again and again, understand, Delete from does not recognize table name alias! Thinking back, the original p

); --connection query, Fong Fong's math score SelectS.sname,sc.core fromStudent S Left JOINSc onS.sid=Sc.sid Left JOINCourse C onC.cid=Sc.cidWHERES.sname= 'Fong Fong'; --Fuzzy Query the student whose name is Ting Select * fromStudentWHERESname like '% ting%'; --query without connection query Tingting's math score SelectS.sid,s.sname,scc.core from(SELECTSid,sname fromStudent) s, (SELECTSid,core,cid fromSC) SCCWHERESname= 'Tingting' andScc.sid=S.sid andScc.cid= 2 ; --Easy multi-

1 description (1) for the MyISAM table, if the auto-increment column is updated using UPDATE, if the column 20540 is repeated with the existing 20540, an error will occur. if the column is greater than the existing maximum 20540 ;, the AUTO_INCREMENT of the

Precautions for using the AUTO_INCREMENT column in MySQL: update auto-incrementing Column1. Description (1) For the MyISAM table, if you use UPDATE to UPDATE the auto-incrementing column, if the

Tags: ase tar strong CopyTo implementation values. NET Targe--Ask a query question for an SQL statement that was encountered during an interviewThe table has a B C three column, implemented with the SQL statement: When column A is greater than

Code highlighting produced by Actipro CodeHighlighter (freeware)http://www.CodeHighlighter.com/--> Alter Table Name Alter Table -Change table attributesSyntax Alter Table Table [ * ] Add [

(8000) Select @sql =isnull (@sql + ' union All ', ') + ' select name, [Course]= ' +quotename (name, ' "') + ', [score] = ' +quotename (name) + ' fro M TB ' from syscolumns WHERE name!= ' name ' and id=object_id (' TB ')--table name TB, not including other columns named name ORDER by Colid exec ( @sql + ' ORDER b

--Requirements change, need to add a foreigner name to the F_username field of the T_login table, the previous set of varchar (10) is not enough, the negotiation decision to change to varchar (30), when executing, the message index ' Uq_f_username ' depends on the column ' F_ UserName '. ALTER TABLE ALTER COLUMN F_USER

Gets the primary key column name of the table SQLSELECT * FROM User_cons_columnswhere constraint_name = (select Constraint_name from user_constraintsWHERE table_name = ' bst_favorite ' and constraint_type = ' P ');Remember : table names are capitalizedPerform the test, the table all the primary keys are detected, the p

Tags: Time characteristics Law object_id LTE Eric modify alter typeOriginal: Use SQL statement to create a modified SQL Server identity column (that is, autogrow column)I. Definition and characteristics of the identity columnThe identity column in

Label:I. Definition and characteristics of the identity columnThe identity column in SQL Server is also called the identifier column, which is also known as the self-increment column.This type of column has the following three characteristics:1. The data type of the column i