Unknown column in where clause. Why? [duplicate]

Question

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Unknown Column In Where Clause (16 answers)

Closed 9 years ago.

I use next query:

SELECT ROUND(r/h) AS conv FROM table WHERE conv > 1

I receive error "Unknown column 'conv' in 'where clause'", But why? After AS conv is it not exists yet?

Answer 1

The column alias isn't available until results are being produced. Try

SELECT ROUND(R / H) AS CONV
  FROM TABLE1
  WHERE ROUND(R / H) > 1

SQLFiddle here.

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