Comment by mootzville | Hacker News Reader

Comment by mootzville | Hacker News Reader

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I was taught to:

1. Write your WHERE clause first 2. Return to the beginning of the line to finish writing the statement 3. Check your statement 4. If it looks good, then -- and only then -- add your closing semicolon

Having said that, once during my second week at a new company, I plugged in an ethernet cable to an APC UPS, so I could set up networking on it. It shut down production. Why? APC makes (for that model at least) proprietary ethernet cables for networking, and if you plug in a regular cable it does an autoshutdown...an engineers attempt at marketing perhaps!? I did RTFM before, and after out of confusion, and there was no mention of this.

I will typically do something like this when writing SQL in an interactive tool:

  SELECT * from table
  WHERE id = 12345

and once that's giving me the selection I want, insert the update statement into the middle:

  SELECT * from table
  -- UPDATE table set c1 = v1, c2 = v2
  WHERE id = 12345

Then, accidentally running the entire buffer doesn't do anything destructive, but selecting the query from update to the end of the statement lets me do the update. (It's still imperfect, because selecting only the update line will still be destructive.)

(Most of the RDBMS tools that I've used would happily ignore the lack of a closing semi-colon and that will not save you for a single-statement case.)

True, thought I didn't include the lookup first, it is how it happens in practice. Also, we use the mysql client, so semicolon is a must, and I would avoid anything that let you submit the statement without it...that's your safety net.

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