Question

我正在使用来自http://openhms.sourceforge.net/sqlbuilder/的Java和SQLBuilder，并且正在尝试动态地构建SQL SELECT查询：

IEnumerator

但是，它会创建如下字符串：

SelectQuery sql = new SelectQuery();
sql.addAllColumns().addCustomFromTable("table1");
sql.addCondition(BinaryCondition.like("column1", "A"));

由于引号错误（SELECT * FROM table1 WHERE ('column1' LIKE 'A')），它无法正常工作。我想它需要'column1'方法中的一些Column对象。有没有办法用适当的引号创建查询？

Answer 1

我找到了解决方案。我必须创建扩展Column的新类CustomSql并将我的列名称作为参数传递：

public class Column extends CustomSql {
   public Column(String str) {
      super(str);
   }
}

然后：

SelectQuery sql = new SelectQuery();
sql.addAllColumns().addCustomFromTable("table1");
sql.addCondition(BinaryCondition.like(new Column("column1"), "A"));

或者没有创建自己的类：

SelectQuery sql = new SelectQuery();
sql.addAllColumns().addCustomFromTable("table1");
sql.addCondition(BinaryCondition.like(new CustomSql("column1"), "A"));

它创建以下SQL查询，工作正常：

SELECT * FROM table1 WHERE (column1 LIKE 'A')

Answer 2

BinaryCondition.like（）接受一个Column Object的对象，然后在内部使用SqlObject将其转换为Converter.toColumnSqlObject(Object)。在findColumn(String columnName)和findSchema(String tableName)中分别有一个名为Class DbTable和Class DbSchema的方法，您可以在其中传递一个简单的String对象。试试这个可以解决你的问题：

 DbTable table1= schema.findSchema("table1");
 DbColumn column1 = table1.findColumn("column1");

 SelectQuery sql = new SelectQuery();
 sql.addAllColumns().addCustomFromTable(table1);
 sql.addCondition(BinaryCondition.like(column1, "A"));

Answer 3

请检查工作示例并重构您自己的查询

String query3 =
      new SelectQuery()
      .addCustomColumns(
          custNameCol,
          FunctionCall.sum().addColumnParams(orderTotalCol))
      .addJoins(SelectQuery.JoinType.INNER, custOrderJoin)
      .addCondition(BinaryCondition.like(custNameCol, "%bob%"))
      .addCondition(BinaryCondition.greaterThan(
                        orderDateCol,
                        JdbcEscape.date(new Date(108, 0, 1)), true))
      .addGroupings(custNameCol)
      .addHaving(BinaryCondition.greaterThan(
                     FunctionCall.sum().addColumnParams(orderTotalCol),
                     100, false))
      .validate().toString();

Answer 4

看看这个库JDSQL（它需要Java 8）：

JQuery jquery = new JQuery();
    Collection<Map<String, Object>> result = jquery.select("tbl1::column1", "tbl2::column2") //Select column list
                                                .from("Table1" , "TB1") // Specifiy main table entry, and you can add alias
                                                .join("Table2::tb2") // Provide your join table, and another way to provide alias name
                                                .on("tbl1.key1", "tbl2.key1") // your on statement will be based on the passed 2 values equaliy 
                                                .join("Table3", "tbl3", true) // Join another table with a flag to enable/disable the join (Lazy Joining)
                                                .on("tbl2.key2", "tbl3.key1", (st-> {st.and("tbl3.condition = true"); return st;}))
                                                .where("tbl1.condition", true, "!=") // Start your where statment and it also support enable/disable flags 
                                                .and("tbl2.condition = true", (st-> {st.or("tbl.cond2", 9000, "="); return st;})) // And statment that is grouping an or inside parentheses to group conditions  
                                                .and("tbl3.cond3=5", false) // And statment with a flag to enable/disable the condition 
                                                .get((String sql, Map<String, Object> parameters)-> getData(sql, parameters)); // Passing the hybrid getter. 
                                                                //You can also assign the getter at the jqueryobject itself by calling setGetter.
}

private static Collection<Map<String, Object>> getData(String sql, Map<String, Object> parameters){



    return null;

}

}

如何用sqlbuilder构建SELECT查询？

4 个答案: