jpql比较字符串为int

Question

I have object called info

class info
@Column(name="id")
int id
@Column(name="system")
string system
@Column(name="triesErrCount")
string triesErrCount

and same type in DB. Now triesErrCount is String (in the class and in DB (varchar)), but in my db it's all like numbers ("1","7","56"...).

I try to get all infos that are less then 50, I try this:

SELECT x from PaymentInfo x where x.triesErr <=:triesErrAsString

triesErrAsString = "50" in jpql

But it's not working, I also try:

class info
@Column(name="id")
int id
@Column(name="system")
string system
@Transient
string triesErrCount
@Column(name="triesErrCount")
int triesErrCountAsInt

SELECT x from PaymentInfo x where x.triesErr <=:triesErrAsInt

triesErrAsInt = 50

But still not working. I'm using jpa 1.0. and OpenJPA 1.2.1

Answer 1

A string is not an Int, so numeric comparisons will not work as you are expecting. You need to convert the string to a numeric to be able to use the numeric operators. See CAST for an example of how you might do that in JPQL, but you might be better off changing the type in the database to a numeric type.