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Java 如何通过条件查询调用使用mysql关键字作为参数的函数？

java jpa

Java 如何通过条件查询调用使用mysql关键字作为参数的函数？,java,jpa,criteria-api,Java,Jpa,Criteria Api,我正在使用mysql和jpa规范查询。 我想知道如何调用使用mysql关键字作为参数的函数 以下是一个例子： select * from schema3.countries order by convert(name using GBK); public class CustomMariaDB53Dialect extends MariaDB53Dialect { private static final Logger LOG = LoggerFactory.getLogger(Cus

我正在使用mysql和jpa规范查询。 我想知道如何调用使用mysql关键字作为参数的函数

以下是一个例子：

select * from schema3.countries order by convert(name using GBK);

public class CustomMariaDB53Dialect extends MariaDB53Dialect {
    private static final Logger LOG = LoggerFactory.getLogger(CustomMariaDB53Dialect.class);

    public CustomMariaDB53Dialect() {
        super();
}

hibernate.dialect=xxx.xxx.CustomMariaDB53Dialect 

Expression<String> countryName = builder().function(
                        "convertEncode", 
                        String.class,
                        join.get(Country_.NAME),
                        builder().literal("gbk")
                );

                return direction.isDescending() ? builder().desc(countryName ) : builder().asc(countryName );

convert
方法，使用
和
GBK
关键字作为参数

我想通过条件查询调用
convert
函数

我尝试了下面的方法，但它对我不起作用


Expression expression = join.get(Country_.NAME);
                Expression orderExpression = builder.function(
                        "convert",
                        String.class,
                        expression,
                        builder.literal("USING GBK")
                );


及

变量
countryNameAlias
为空，因此无法工作

以下是错误：


Hibernate: select expert0_.id as id1_14_, expert0_.code as code2_14_, expert0_.created_at as created_3_14_, expert0_.expert_information as expert_i4_14_, expert0_.meta_data_of_the_expert_information as meta_dat5_14_, expert0_.motherland as motherla8_14_, expert0_.number_of_applications as number_o6_14_, expert0_.updated_at as updated_7_14_, JSON_EXTRACT(expert0_.expert_information, '$.basicInformation.birthDate') as formula4_, case
           when
               JSON_EXTRACT(expert0_.expert_information, '$.basicInformation.gender') = 'MALE'
            then 0
else 1 end as formula5_, JSON_EXTRACT(expert0_.expert_information, '$.basicInformation.nameEN') as formula6_, convert(JSON_EXTRACT(expert0_.expert_information, '$.basicInformation.nameZH') using GBK) as formula7_ from expert expert0_ left outer join expert_application_record expertappl1_ on expert0_.id=expertappl1_.expert_id left outer join countries country2_ on expert0_.motherland=country2_.id where expertappl1_.latest=? order by convert(?) desc limit ?
2019-11-05 18:58:41.281 TRACE 15252 --- [nio-8080-exec-2] o.h.type.descriptor.sql.BasicBinder      : binding parameter [1] as [BOOLEAN] - [true]
2019-11-05 18:58:41.281 TRACE 15252 --- [nio-8080-exec-2] o.h.type.descriptor.sql.BasicBinder      : binding parameter [2] as [VARCHAR] - [null USING GBK]
2019-11-05 18:58:41.282  WARN 15252 --- [nio-8080-exec-2] o.h.engine.jdbc.spi.SqlExceptionHelper   : SQL Error: 1064, SQLState: 42000
2019-11-05 18:58:41.282 ERROR 15252 --- [nio-8080-exec-2] o.h.engine.jdbc.spi.SqlExceptionHelper   : You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near ') desc limit 10' at line 5
2019-11-05 18:58:41.285 ERROR 15252 --- [nio-8080-exec-2] o.a.c.c.C.[.[.[/].[dispatcherServlet]    : Servlet.service() for servlet [dispatcherServlet] in context with path [] threw exception [Request processing failed; nested exception is org.springframework.dao.InvalidDataAccessResourceUsageException: could not extract ResultSet; SQL [n/a]; nested exception is org.hibernate.exception.SQLGrammarException: could not extract ResultSet] with root cause

java.sql.SQLSyntaxErrorException: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near ') desc limit 10' at line 5
    at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:118) ~[mysql-connector-java-8.0.11.jar:8.0.11]
    at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:95) ~[mysql-connector-java-8.0.11.jar:8.0.11]
    at com.mysql.cj.jdbc.exceptions.SQLExceptionsMapping.translateException(SQLExceptionsMapping.java:122) ~[mysql-connector-java-8.0.11.jar:8.0.11]
    at com.mysql.cj.jdbc.ClientPreparedStatement.executeInternal(ClientPreparedStatement.java:960) ~[mysql-connector-java-8.0.11.jar:8.0.11]
    at com.mysql.cj.jdbc.ClientPreparedStatement.executeQuery(ClientPreparedStatement.java:1019) ~[mysql-connector-java-8.0.11.jar:8.0.11]
    at com.zaxxer.hikari.pool.ProxyPreparedStatement.executeQuery(ProxyPreparedStatement.java:52) ~[HikariCP-2.7.9.jar:na]



谢谢大家。
我将sql更改为：


select *, convert(name using GBK) as nameGBK from schema3.countries order by nameGBK;


因此，下一个问题是如何将计算列添加到选择中。
我们可以在国家/地区模型中添加一列。
字段名为
nameGBK
，使用@Formula注释；
这是密码


    @Column(nullable = false, unique = true)
    private String name;

    @Formula("convert(name using GBK)")
    private String nameGBK;


然后在条件查询中，我们可以按
nameGBK
排序。
代码如下：


builder.desc(join.get(Country_.NAME_GBK));



public class CustomMariaDB53Dialect extends MariaDB53Dialect {
    private static final Logger LOG = LoggerFactory.getLogger(CustomMariaDB53Dialect.class);

    public CustomMariaDB53Dialect() {
        super();
        registerKeyword("using");
        registerKeyword("USING");
        registerKeyword("GBK");
        registerKeyword("gbk");
    }
}



public class CustomMariaDB53Dialect extends MariaDB53Dialect {
    private static final Logger LOG = LoggerFactory.getLogger(CustomMariaDB53Dialect.class);

    public CustomMariaDB53Dialect() {
        super();
        registerFunction("convertEncode", new SQLFunctionTemplate(StandardBasicTypes.STRING, "convert(?1 using ?2)"));
    }
}


但是我使用的jpa无法解析关键字
using
和
GBK
，因此我们必须扩展
您正在使用的方言并注册关键字

代码如下：


builder.desc(join.get(Country_.NAME_GBK));



public class CustomMariaDB53Dialect extends MariaDB53Dialect {
    private static final Logger LOG = LoggerFactory.getLogger(CustomMariaDB53Dialect.class);

    public CustomMariaDB53Dialect() {
        super();
        registerKeyword("using");
        registerKeyword("USING");
        registerKeyword("GBK");
        registerKeyword("gbk");
    }
}



public class CustomMariaDB53Dialect extends MariaDB53Dialect {
    private static final Logger LOG = LoggerFactory.getLogger(CustomMariaDB53Dialect.class);

    public CustomMariaDB53Dialect() {
        super();
        registerFunction("convertEncode", new SQLFunctionTemplate(StandardBasicTypes.STRING, "convert(?1 using ?2)"));
    }
}


并更改配置，告诉hibernate您正在使用新的方言。
如果您使用的是spring数据jpa。
下面是配置：


spring:
  h2:
    console:
      enabled: true
  datasource:
    url: jdbc:mysql://dev:13306/schema3?useSSL=false&allowPublicKeyRetrieval=true&serverTimezone=GMT%2B8&zeroDateTimeBehavior=CONVERT_TO_NULL&nullCatalogMeansCurrent=true
    username: root
    password: root
    driver-class-name: com.mysql.cj.jdbc.Driver
    initialization-mode: always
  liquibase:
    enabled: false
  jpa:
    hibernate:
      ddl-auto: update
    show-sql: true
    properties:
      hibernate:
        order_inserts: true
        #here to tell the hibernate you are using a new dialect.
        dialect: com.hide.hide.CustomMariaDB53Dialect
        jdbc:
          batch_size: 100



spring:
  jpa:
    hibernate:
    properties:
      hibernate:
        dialect: xxx.xxx.CustomMariaDB53Dialect



如果这有助于你给我投票，请。谢谢。
公式不能与本机查询一起使用。
以下是链接：

我对jpa不太熟悉，但这里有一个比使用
@Formula
注释更好的解决方案

首先，您需要创建一个自定义方言
以下是一个例子：


select * from schema3.countries order by convert(name using GBK);



public class CustomMariaDB53Dialect extends MariaDB53Dialect {
    private static final Logger LOG = LoggerFactory.getLogger(CustomMariaDB53Dialect.class);

    public CustomMariaDB53Dialect() {
        super();
}



hibernate.dialect=xxx.xxx.CustomMariaDB53Dialect 



Expression<String> countryName = builder().function(
                        "convertEncode", 
                        String.class,
                        join.get(Country_.NAME),
                        builder().literal("gbk")
                );

                return direction.isDescending() ? builder().desc(countryName ) : builder().asc(countryName );


然后将一个函数注册到方言中
代码如下：


builder.desc(join.get(Country_.NAME_GBK));



public class CustomMariaDB53Dialect extends MariaDB53Dialect {
    private static final Logger LOG = LoggerFactory.getLogger(CustomMariaDB53Dialect.class);

    public CustomMariaDB53Dialect() {
        super();
        registerKeyword("using");
        registerKeyword("USING");
        registerKeyword("GBK");
        registerKeyword("gbk");
    }
}



public class CustomMariaDB53Dialect extends MariaDB53Dialect {
    private static final Logger LOG = LoggerFactory.getLogger(CustomMariaDB53Dialect.class);

    public CustomMariaDB53Dialect() {
        super();
        registerFunction("convertEncode", new SQLFunctionTemplate(StandardBasicTypes.STRING, "convert(?1 using ?2)"));
    }
}



registerFunction
方法的第一个参数是函数名

第二个是
SqlFunction


-1
和
-2
表示函数的参数
因此，函数模板是
convert（？1使用？2）

完成上述测试后

您应该告诉hibernate您正在使用新的方言

配置的路径是
hibernate.dialogue

以下是一个例子：


select * from schema3.countries order by convert(name using GBK);



public class CustomMariaDB53Dialect extends MariaDB53Dialect {
    private static final Logger LOG = LoggerFactory.getLogger(CustomMariaDB53Dialect.class);

    public CustomMariaDB53Dialect() {
        super();
}



hibernate.dialect=xxx.xxx.CustomMariaDB53Dialect 



Expression<String> countryName = builder().function(
                        "convertEncode", 
                        String.class,
                        join.get(Country_.NAME),
                        builder().literal("gbk")
                );

                return direction.isDescending() ? builder().desc(countryName ) : builder().asc(countryName );


如果您使用的是SpringBootJPA

以下是配置：


spring:
  h2:
    console:
      enabled: true
  datasource:
    url: jdbc:mysql://dev:13306/schema3?useSSL=false&allowPublicKeyRetrieval=true&serverTimezone=GMT%2B8&zeroDateTimeBehavior=CONVERT_TO_NULL&nullCatalogMeansCurrent=true
    username: root
    password: root
    driver-class-name: com.mysql.cj.jdbc.Driver
    initialization-mode: always
  liquibase:
    enabled: false
  jpa:
    hibernate:
      ddl-auto: update
    show-sql: true
    properties:
      hibernate:
        order_inserts: true
        #here to tell the hibernate you are using a new dialect.
        dialect: com.hide.hide.CustomMariaDB53Dialect
        jdbc:
          batch_size: 100



spring:
  jpa:
    hibernate:
    properties:
      hibernate:
        dialect: xxx.xxx.CustomMariaDB53Dialect


最后一步是在查询中使用该函数

以下是一个例子：


select * from schema3.countries order by convert(name using GBK);



public class CustomMariaDB53Dialect extends MariaDB53Dialect {
    private static final Logger LOG = LoggerFactory.getLogger(CustomMariaDB53Dialect.class);

    public CustomMariaDB53Dialect() {
        super();
}



hibernate.dialect=xxx.xxx.CustomMariaDB53Dialect 



Expression<String> countryName = builder().function(
                        "convertEncode", 
                        String.class,
                        join.get(Country_.NAME),
                        builder().literal("gbk")
                );

                return direction.isDescending() ? builder().desc(countryName ) : builder().asc(countryName );


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