[CubicsRube]

I'm used to writing the SELECT query and adding the commented-out DELETE just below the SELECT line.

  SELECT *
  -- DELETE
  FROM Sales
  WHERE Customer = 1

Next, selecting the whole query and executing it. If results are satisfactory - selecting only the DELETE part.

[piaste]

This is the one I use too. Tiny difference - I write

   select * -- delete
   from sales
   where customer = 1

so it's even harder to accidentally highlight the 'delete' part.

Although I've switched to DBeaver for a year now, and it automatically pops up a warning when it detects a DELETE query without a WHERE, which is very nice.

[samus]

DBeaver has something even better, albeit sometimes annoying: you can define a connection as "Production" (highlighted red) and "Test" (green). On Production systems, DBeaver will ask you for confirmation for every write statement.