The MERGE statement runs insert, update, or delete operations on a target table from the results of a join with a source table. For example, synchronize two tables by inserting, updating, or deleting rows in one table based on differences found in the other table....
The MERGE statement runs insert, update, or delete operations on a target table from the results of a join with a source table. For example, synchronize two tables by inserting, updating, or deleting rows in one table based on differences found in the other table....
Because the MERGE statement performs a full table scan of both the source and target tables, I/O performance can be affected when using the TOP clause to modify a large table by creating multiple batches. In this scenario, it is important to ensure that all successive batches target new rows...
there are two circles that represent two tables and can be considered as Source and a Target. The MERGE statement tries to compare the source table with the target table based on a key field and then do some of the processing. The MERGE statement actually combines the INSERT, UPDATE, ...
Perform a simple one-way synchronization of two tables. CREATE TABLE SourceTable ( Col1 INT NOT NULL PRIMARY KEY, Col2 VARCHAR(20) NOT NULL ); CREATE TABLE TargetTable ( Col1 INT NOT NULL PRIMARY KEY, Col2 VARCHAR(20) NOT NULL ); ...
A full outer join retrieves both matching rows and nonmatching rows from both tables. (full join把所有满足和不满足条件的行全部列出来) 如果要得出和merge一样的效果,需要加入coalesce函数 COALESCE(argument-1<...,argument-n>) The COALESCE function checks the value of each argument in the order in...
对于SQL Server 2008和更高版本,Microsoft引入了非常有用的MERGE操作,该操作与上述INNER JOIN方法类似,但是MERGE尝试同时执行UPDATE和INSERT命令。 Thiseffectively synchronizesthe two tables based on the query performed, updating and inserting records as necessary for the two to match. ...
The above illustration depicts how a SQL MERGE statement basically works. As you can see, there are two circles that represent two tables and can be considered as Source and a Target. The MERGE statement tries to compare the source table with the target table based on a key field and then...
When you create your using clause with a MERGE statement, keep a few things in mind. First, when you use a sub query in the using clause, it can of course be a table, but it can also be a query against one or more other tables, or even a stored view. The view must be updatabl...
JOIN Three Tables The following SQL statement selects all orders with customer and shipper information: Here is theShipperstable: ShipperIDShipperNamePhone 1Speedy Express(503) 555-9831 2United Package(503) 555-3199 3Federal Shipping(503) 555-9931 ...