CSV第二次导入后，MySQL值更新为最大值

Question

I'm using a php script to import values from a CSV files to table1 and then using inner join to update a field of table2 from table1:

UPDATE table2 AS t2
INNER JOIN
  (
  SELECT field, id
  FROM table1  ) AS t1 ON (t2.id=t1.id)
SET t2.field = t2.field+t1.field;

however, if I perform two imports the fields that were updated in the first import and not in the second are being updated to max value 9999.999 , field type Decimal(7,3). Any ideas why and what might a suitable fix be? P.S the values in the table1 are correct.

Answer 1

use simple update syntax

UPDATE table2 AS t2, table1 AS t1
SET t2.field = t2.field+t1.field
WHERE (t2.id=t1.id)