This option takes a list of one or more partitions or subpartitions (or both).
Only the partitions (or subpartitions) listed are checked for matches, and a row that is not in any of these partitions or subpartitions is not updated, whether it satisfies the clause, are flagged as unsafe for statement-based replication.
He is also the founder of Database Star.com, a website that teaches database developers how to improve their skills and their career.
The UPDATE statement is used to change values in one, or more, or all of the records in a table.
It can also reduce the number of steps required to update your data by compressing two or more queries into a single query.
Sql updating a query result set
Ben Brumm is a software consultant with over 10 years experience in the IT industry.There is a page in the online documentation that explains safe mode entitled 'safe Server Startup Script'.Suppose you have a table where each row is associated with a certain group (For example, orders are associated with the customers placing them) where each item WITHIN the group has a distinct number (For example, each person my have a sequence of competition results - each person, therefore, has a 1st, 2nd, 3rd... If you would like to renumber items within their group so that each has the same baseline (say 0), here is an example way to proceed: Create TEMPORARY Table Groups (Id INTEGER AUTO_INCREMENT PRIMARY KEY, Name VARCHAR(31), Group Id VARCHAR(31), Val Within Group INTEGER); INSERT INTO Groups VALUES (null, "Davy", "Boy", 2); INSERT INTO Groups VALUES (null, "Mary", "Girl", 2); INSERT INTO Groups VALUES (null, "Bill", "Boy", 5); INSERT INTO Groups VALUES (null, "Jill", "Girl", -3); INSERT INTO Groups VALUES (null, "Fred", "Boy", 3);# Find the lowest value for each group CREATE TEMPORARY TABLE Group Sum AS SELECT Group Id, MIN(Val Within Group) AS base Val FROM Groups GROUP BY Group Id;# create an index so my SQL can efficiently match ALTER TABLE Group Sum ADD UNIQUE (Group Id);# finally, make the baseline adjustment UPDATE Groups LEFT JOIN Group Sum USING (Group Id) SET Val Within Group=Val Within Group-base Val; SELECT * FROM Groups;# 1 Davy Boy 0# 2 Mary Girl 5# 3 Bill Boy 3# 4 Jill Girl 0# 5 Fred Boy 1#Each group ("Boy", "Girl") now has a (lowest) Val Within Group entry of 0.However, instead of setting a specific price, they want to make it 20% higher than the most expensive product they have.To do this, we can use a subquery in the SET clause.However, if a relationship has been configured to enable cascading operations, for example by using Microsoft Access or DAO (Data Access Objects) , the Jet SQL UPDATE and DELETE) statements will cascade.The UPDATE statement can be used in updating a single field in a table. If you want to know which records will be modified, first run a SELECT query that uses the same criteria.The data for this is stored in the order_line table.The subquery will perform a COUNT function using a CASE statement to determine if the returned value is Y or N depending on the value of COUNT.Finally, the WHERE clause is outside the subquery to only update the product_id of 1, as it applies to UPDATE rather than to the subquery.Using the data from the previous example (the product table), the company wants to deactivate all the products that have not had an order placed for them.