中位数

使用示例

import com.youngdatafan.sqlbuilder.enums.DatabaseType;
import com.youngdatafan.sqlbuilder.enums.FunctionType;
import com.youngdatafan.sqlbuilder.model.Function;
import com.youngdatafan.sqlbuilder.model.Model;
import com.youngdatafan.sqlbuilder.model.Query;
import com.youngdatafan.sqlbuilder.model.Schema;
import com.youngdatafan.sqlbuilder.model.Table;

public class Test {

    @org.junit.Test
    public void getFunction() {
        Schema schema = Schema.getSchema("");
        Table test = Table.getOriginalTable(schema, "test", "t");
     
        Query query = new Query();
        Model num = test.addField("num");
        Function function = Function.getFunction(FunctionType.MEDIAN, num);
        query.addColumn("val", function);
        query.addFrom(test);
        System.out.println("oracle：");
        System.out.println(query.getDatabaseSql(DatabaseType.ORACLE));
        System.out.println();
       
        System.out.println("pg：");
        System.out.println(query.getDatabaseSql(DatabaseType.POSTGRESQL));
        System.out.println();
       
        System.out.println("clickhouse：");
        System.out.println(query.getDatabaseSql(DatabaseType.CLICKHOUSE));
        System.out.println();
        
        System.out.println("kdw：");
        System.out.println(query.getDatabaseSql(DatabaseType.KDW));
        System.out.println();
    }
}

根据数据源获取对于数据库的sql。

ORACLE

SELECT MEDIAN(t."num") AS "val" FROM "test" t  

POSTGRESQL

SELECT percentile_disc(0.5) within group (order by t.num) AS val FROM test t 

CLICKHOUSE

SELECT median(t.num) AS val FROM test t

KDW

SELECT percentile_disc(0.5) within group (order by t.num) AS val FROM test t