Not Condition in 'If Case' Statement

Match/Case not condition

I don't think you can use not in structural pattern matching, an alternative is to capture the values you need and then use the default _ case to be the 'not' expression.

a = 5
match a:
    case 10:
        print(a)
    case _:
        print("not 10")

EDIT:
I was curious and did some research, turns out a negative match was rejected.
https://www.python.org/dev/peps/pep-0622/#negative-match-patterns

not in condition not working with Case statement PLSQL

That must be because IN isn't appropriate in this context. You should switch to something else, e.g. separate LIKE conditions:

No:

WHEN p.proj_comp_id NOT IN ( '5207-%', '1051-%', '1050-%', etc.

Yes:

 WHEN p.proj_comp_id NOT LIKE '5207-%'
  AND p.proj_comp_id NOT LIKE '1051-%'
  AND p.proj_comp_id NOT LIKE '1050-%'
  etc.

SQL Where Clause with CASE & NOT IN Condition

You can use CASE in WHERE as Shown below:

    WHERE 1=(
             CASE WHEN @X = 0 and @y = 0 and pagecode not in ('admin','external') THEN 1
                  WHEN @x = 0 and @y = 1 and pagecode not in ('admin') THEN 1
                  WHEN @x = 1 and @y = 0 and pagecode not in ('external') THEN 1
                  ELSE 0 END
            )

this will not return any row if @x=1 and @y=1.
If you want to return all rows if @x=1 and @y=1

    WHERE 1=(
             CASE WHEN @X = 0 and @y = 0 and pagecode not in ('admin','external') THEN 1
                  WHEN @x = 0 and @y = 1 and pagecode not in ('admin') THEN 1
                  WHEN @x = 1 and @y = 0 and pagecode not in ('external') THEN 1
                  WHEN @x = 1 and @y = 1 THEN 1
                  ELSE 0 END
            )

If not condition statement in python

if is the statement. not start is the expression, with not being a boolean operator.

not returns True if the operand (start here) is considered false. Python considers all objects to be true, unless they are numeric zero, or an empty container, or the None object or the boolean False value. not returns False if start is a true value. See the Truth Value Testing section in the documentation.

So if start is None, then indeed not start will be true. start can also be 0, or an empty list, string, tuple dictionary, or set. Many custom types can also specify they are equal to numeric 0 or should be considered empty:

>>> not None
True
>>> not ''
True
>>> not {}
True
>>> not []
True
>>> not 0
True

Note: because None is a singleton (there is only ever one copy of that object in a Python process), you should always test for it using is or is not. If you strictly want to test tat start is None, then use:

if start is None:

Skip/Ignore a condition in CASE statement in SQL

If you want the variable you are creating with CASE expression to be NULL then use the appropriate null or missing value in the CASE expression.

Perhaps you mean you want to create the new colB variable to have the existing colB variable's value when it is not P or Q?

select colA
     , case
         when colB = 'P' then colC 
         when colB = 'Q' then colD
         else colB
       end as new_colB
from table_A

If you don't want the observations with COLB='R' in the results then exclude those using WHERE.

select colA
     , case
         when colB = 'P' then colC 
         when colB = 'Q' then colD
         else colB
       end as new_colB
from table_A
where colB ne 'R'

If you are actually using SAS then skip the SQL completely and just write SAS code to do whatever you want. Then you could actually have statements that are executed conditionally.

data want;
  set mylib.table_A;
  if colB='P' then do;
     * some other data step statements ;
  end;
run;

usage of !(not) operator in switch case

!0 evals to true, which is not equals to 1 or 2.

Consider writing it in this way:

for (let number = 1; number <= 100; number++) {

 switch (number % 3) {

  case 0:

   console.log(`${number} is multiple of 3`)

   break;

  default:

   console.log(`${number} is not multiple of 3`);

 }

}

Select Case value
    Case 1, 2
        DoWork()
End Select

Select Case myComboBox.SelectedIndex
    Case 1, 5, 8
        'The suggestion is acceptable, so process it
        DoWork()
    Case Else
        'The suggestion is invalid, so show an error
        MessageBox.Show("You cannot select that option. " & _
                        "Please choose options 1, 5, or 8 instead.", _
                        "Invalid Selection", _
                        MessageBoxButtons.OK, MessageBoxIcon.Error)
End Select