What kind of SQL clause is this? Any way to convert it to SQL?
what kind of SQL is this?
开发者_如何学运维SELECT IFNULL(SUM(prenotazione.VALUTAZIONE),0) AS somma,
COUNT(*) AS numero
FROM `prenotazione`
WHERE prenotazione.USER_ID=18793 AND
prenotazione.PRENOTAZIONE_STATO_ID IN (10,11)
I'm using propel as my ORM.
Any way to convert that kind of SQL to Mysql SQL?
This query is valid in MySQL. It selects all rows from the prenotazione
table where the user_id
is 18793 and the prenotazione_stato_id
is 10 or 11. The resulting rows are summarized: in the numero
column you get the number of rows found, in the somma
column you get the sum of the valutazione
values. If no rows were selected, SUM()
would return NULL
. To prevent this, IFNULL([expr1],[expr2])
is applied, which returns [expr1]
if it is not null, and [expr2]
if it is null. This makes sure you always return a number.
There is no easy way to do this with Propel, since your result cannot be easily mapped to a Propel object. The best thing you can do is use the underlying database layer (PDO) to escape your parameters and handle the resultset, and you don't open an extra database connection or something like that.
When considering portability, Standard SQL is your friend. This query can be very easily transformed into Standard SQL-92:
- Terminate the statement with a semi-colon.
- Replace
IFNULL
withCOALESCE
. - Remove the single quotes from the table name.
With better spacing it could look like this:
SELECT COALESCE(SUM(prenotazione.VALUTAZIONE), 0) AS somma,
COUNT(*) AS numero
FROM prenotazione
WHERE prenotazione.USER_ID = 18793
AND prenotazione.PRENOTAZIONE_STATO_ID IN (10,11);
That said, for MySQL you probably would need to undo step 3... which leads me to suspect it was MySQL syntax in the first place.
Using Babelfish to give a rough translation from Italian to English results in
SELECT IFNULL(SUM(reservation.APPRAISAL),0) AS sum,
COUNT(*) AS number
FROM `reservation`
WHERE reservation.USER_ID=18793 AND
reservation.RESERVATION_STATE_ID IN (10,11)
Share and enjoy.
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