Delete rows using case when condition in SQL Server

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Say I write this query

select
    x1, x2, x3 act
from 
    mytab

I need delete rows using any condition

case when x1=b, and act=0, then delete these rows

At the same time, i need to delete rows that contain a null value by x1 column.

How can I do that?

You specified the condition in WHERE clause

for the condition that you required

DELETE d
FROM   mytab d
WHERE (
          d.x1 = 'b' AND d.act = 0
      )
OR    d.x1 is null

Using CASE with Data Modifying Statements, What happens when you combine CASE with SQL's data modifying statements? UPDATE – Changes values in table columns; DELETE – Removes records from the table This new table will be created with the query. Syntax of the DELETE Statement. You may want to delete rows because they are no longer needed, or they were incorrectly added in the first place. The DELETE statement is used to remove rows from a SQL Server table. A single DELETE statement can remove a single row, or number of rows.

In MySQL use where clause

DELETE FROM mytab 
WHERE x1 = b AND act=0 OR x1 IS NULL;;

Just execute this SQL and done. It will delete rows from database matching these conditions.

Delete with in case statement – SQLServerCentral, DELETE t from table t where 1 = case when <condition> then 1 else 0 end The CASE statement provides conditional evaluation inside of a SQL statement, the rows you want to delete, then change the query to a DELETE:. The CASE statement provides conditional evaluation inside of a SQL statement, but it is used to output a single value within a field evaluation, join term, where clause, etc. That is why Ninja's answer had to create a case statement that outputted a value of 1 if condition was true,

For deleting rows,use Delete statement instead of select and the table name and then where clause for putting condition

 Detele t1
     from mytab t1
    where 
     (  x1=b  and act=0
     ) OR x1 IS NULL

here t1 is alias of table mytab

SQL Server: DELETE Statement, This SQL Server tutorial explains how to use the DELETE statement in SQL is used to delete a single record or multiple records from a table in SQL Server. The rows that cause the search_condition evaluates to true will be deleted. The WHERE clause is optional. If you skip it, the DELETE statement will remove all rows from the table. SQL Server DELETE statement examples. Let’s create a new table for the demonstration.

How to Delete a Row (one or More) Using CASE Statement , In the simplest scenarios, you would use the case statement in either of two ways: 1 - modify the contents of the WHERE clauses 2 - create a  Conditional Deleting in SQL? Ask Question How can I delete all line items with the Rev Code of 3 where the following condition is met: sql sql-server delete-row.

DELETE (Transact-SQL), Specifies the conditions used to limit the number of rows that are deleted. If a WHERE clause is not supplied, DELETE removes all the rows from  In the order specified, evaluates input_expression = when_expression for each WHEN clause. Returns the result_expression of the first input_expression = when_expression that evaluates to TRUE. If no input_expression = when_expression evaluates to TRUE, the SQL Server Database Engine returns the else_result_expression

SQL Server DELETE, For example, the following statement will delete all rows from the target_table : In this case, you need to specify the search_condition in the WHERE clause to  The SQL DELETE Statement. The DELETE statement is used to delete existing records in a table. DELETE FROM table_name WHERE condition; Note: Be careful when deleting records in a table! Notice the WHERE clause in the DELETE statement. The WHERE clause specifies which record(s) should be deleted.

Comments
  • The DELETE query would be DELETE FROM dbo.mytab WHERE x1 = 'B' AND act=0 OR x1 IS NULL;.
  • Why the parenthesis?
  • it is required for the AND conditions
  • Thanks, so it doesn't follow the standard operators priorities. In C I would write: x && y || z whitout parenthesis.