mysql - 在 HQL 中使用 CAST(columnName AS INT)

Question

我正在使用 Hibernate 4 和 Postgres

以下查询是两个表的连接，我需要将一个 varchar 列转换为整数，以便按顺序检索某些值。 HQL 支持这个吗？文档是这样说的，但我得到如下异常

Query query  = session.createQuery("SELECT DISTINCT a.attributeName, a.displayName, CAST(a.seqNo AS INTEGER) FROM Entitydefinitionconcrete a, Entitymasterconcrete b WHERE (a.entityTypeId=b.concreteEntityId AND b.baseType=:baseType) AND a.viewGrid=:flag ORDER BY CAST(a.seqNo AS INTEGER)");
query.setParameter("baseType","test");
query.setParameter("flag", true);
query.list();

异常:

HHH000203: processEqualityExpression() : No expression to process!
org.hibernate.hql.internal.ast.QuerySyntaxException: expecting CLOSE, found '.' near line 1, column 70 [SELECT DISTINCT a.attributeName, a.displayName, CAST(a.seqNo AS Types.INTEGER) FROM com.tcs.oss.tims.common.entityBeans.Entitydefinitionconcrete a, com.tcs.oss.tims.common.entityBeans.Entitymasterconcrete b WHERE (a.entityTypeId=b.concreteEntityId AND b.baseType=:baseType) AND a.viewGrid=:flag ORDER BY CAST(a.seqNo AS INTEGER)]
     at org.hibernate.hql.internal.ast.QuerySyntaxException.convert(QuerySyntaxException.java:54)
    at org.hibernate.hql.internal.ast.QuerySyntaxException.convert(QuerySyntaxException.java:47)
    at org.hibernate.hql.internal.ast.ErrorCounter.throwQueryException(ErrorCounter.java:79)
    at org.hibernate.hql.internal.ast.QueryTranslatorImpl.parse(QueryTranslatorImpl.java:278)
   at org.hibernate.hql.internal.ast.QueryTranslatorImpl.doCompile(QueryTranslatorImpl.java:182)

Answer 1

DOC说，

cast(... as ...), where the second argument is the name of a Hibernate type, and 
extract(... from ...) if ANSI cast() and extract() is supported by the underlying database

E.G : cast(propName as integer)