How to create OrderSpecifier in QueryDSL for TIME difference?

Question

I want to create a querydsl OrderSpecifier expression that orders by the minutes difference of two sql TIME values:

@Generated
public class QStock extends EntityPathBase<Stock> {
    public final TimePath<java.time.LocalTime> time1 = createTime(..);
    public final TimePath<java.time.LocalTime> time2 = createTime(..);
}

Pseudocode:

QStock.stock.time1.minutesTo(QStock.stock.time2).desc();

Of course the minutesTo() method does not exist. But how can I achieve this?

Of course there is no need that the difference is calculated in minutes. I just want to put the biggest difference between those 2 times sorted topdown.

I tried as follows, but getting an exception:

Expressions.numberOperation(Integer.class, Ops.DateTimeOps.DIFF_MINUTES, QStock.stock.time1, QStock.stock.time2)


Caused by: java.sql.SQLSyntaxErrorException: (conn=1326) FUNCTION table.diff_minutes does not exist
    at org.mariadb.jdbc.internal.util.exceptions.ExceptionMapper.get(ExceptionMapper.java:236) ~[mariadb-java-client-2.3.0.jar:?]
    at org.mariadb.jdbc.internal.util.exceptions.ExceptionMapper.getException(ExceptionMapper.java:165) ~[mariadb-java-client-2.3.0.jar:?]

So I tried adding the TIMEDIFF function string explicit to querydsl:

//inspired by Ops.DateTimeOps
enum MysqlDateTimeOps implements Operator {
    TIMEDIFF(Comparable.class);

    private final Class<?> type;

    MysqlDateTimeOps(Class<?> type) {
        this.type = type;
    }

    @Override
    public Class<?> getType() {
        return type;
    }
}

Using:

Expressions.numberOperation(Integer.class, MysqlDateTimeOps.TIMEDIFF, QStock.stock.time1, QStock.stock.time2)

Result:

org.springframework.dao.InvalidDataAccessApiUsageException: No pattern found for TIMEDIFF; nested exception is java.lang.IllegalArgumentException: No pattern found for TIMEDIFF
    at org.springframework.orm.jpa.EntityManagerFactoryUtils.convertJpaAccessExceptionIfPossible(EntityManagerFactoryUtils.java:373) ~[spring-orm-5.1.9.RELEASE.jar:5.1.9.RELEASE]
    at org.springframework.orm.jpa.vendor.HibernateJpaDialect.translateExceptionIfPossible(HibernateJpaDialect.java:255) ~[spring-orm-5.1.9.RELEASE.jar:5.1.9.RELEASE]
    at org.springframework.orm.jpa.AbstractEntityManagerFactoryBean.translateExceptionIfPossible(AbstractEntityManagerFactoryBean.java:527) ~[spring-orm-5.1.9.RELEASE.jar:5.1.9.RELEASE]
    at org.springframework.dao.support.ChainedPersistenceExceptionTranslator.translateExceptionIfPossible(ChainedPersistenceExceptionTranslator.java:61) ~[spring-tx-5.1.9.RELEASE.jar:5.1.9.RELEASE]
    at org.springframework.dao.support.DataAccessUtils.translateIfNecessary(DataAccessUtils.java:242) ~[spring-tx-5.1.9.RELEASE.jar:5.1.9.RELEASE]
    at org.springframework.dao.support.PersistenceExceptionTranslationInterceptor.invoke(PersistenceExceptionTranslationInterceptor.java:153) ~[spring-tx-5.1.9.RELEASE.jar:5.1.9.RELEASE]

So how can I use the TIMEDIFF function then in querydsl?

Answer 1

尽管我希望有一个更简单的解决方案，但仍可以进行以下工作：

Expressions.timeTemplate(Integer.class, "TIMEDIFF({0}, {1})", Arrays.asList(QStock.stock.time1, QStock.stock.time2));