Can we write case statement in where clause?
CASE can be used in any statement or clause that allows a valid expression. For example, you can use CASE in statements such as SELECT, UPDATE, DELETE and SET, and in clauses such as select_list, IN, WHERE, ORDER BY, and HAVING.
How do I update using join?
The most easiest and common way is to use join clause in the update statement and use multiple tables in the update statement.
- UPDATE table 1.
- SET Col 2 = t2.Col2,
- Col 3 = t2.Col3.
- FROM table1 t1.
- INNER JOIN table 2 t2 ON t1.Col1 = t2.col1.
- WHERE t1.Col1 IN (21,31)
Is it possible to update multiple columns in SQL?
An equivalent valid SQL update would be: Of course this isn’t pretty and requires repeating the same cases (e.g. ‘name1’) multiple times, but I just don’t think it’s possible any other way. If there are any additional NOT NULL columns without a default value, you’ll have to add dummy values for those.
Is there a problem with using a case in an UPDATE statement?
I know this is a very old question and the problem is marked as fixed. However, if someone with a case like mine where the table have trigger for data logging on update events, this will cause problem. Both the columns will get the update and log will make useless entries.
When do you touch both columns in an update?
Both columns specified in the SET clause of your UPDATE are going to be touched (written to) for all the rows matching the some_more_conditions, no matter what x_specific_condition or y_specific_condition may evaluate to. There is no syntax to work around that while sticking to a single statement.
How to use case statement to update VAL3?
You can use single ‘WHEN’ for updating val3 since the value to be updated is same in all cases. Note: DO NOT USE SWITCH CASE ON update statements. Write a single query each time you want to update. If you want to automate the process of writing the query, use an excel sheet to concat expression and create queries and run them.