php - Variable in SQL not working with prepare statement

You can rewrite this query without using a MySQL variable..

INSERT INTO
GSM_Parent (OrderNumber)
values ( (SELECT COALESCE( MAX( OrderNumber ) , 0 ) +1 FROM GSM_Parent) )

Thanks, but I got the following error:#1093 - You can't specify target
table 'GSM_Parent' for update in FROM clause .

Indeed i missed you used the same table twice, the query below should work.

INSERT INTO
  GSM_Parent (OrderNumber)
VALUES (
   (SELECT OrderNumber FROM (
     SELECT
       (COALESCE(MAX(OrderNumber), 0) + 1) AS OrderNumber
     FROM
       GSM_Parent
     ) AS GSM_Parent
   )
)

@Jarth 's query from the comments is also possible then you need to write

INSERT INTO
  GSM_Parent (OrderNumber)
SELECT
  OrderNumber
FROM(
   SELECT COALESCE(MAX(OrderNumber), 0) +1 AS OrderNumber FROM GSM_Parent
) AS GSM_Parent