动态创建JOOQ查询

我需要根据参数集动态创建JOOQ SELECT查询。 我不知道如何动态追加它。 请帮忙

提前致谢。

Answer 1

jOOQ有两种类型的API来构造查询。

• 允许在Java代码中创建内联SQL语句的DSL API，例如

  create.select(TA, TB).from(T).where(TXeq(3).and(TYeq(5))); 

• 允许增量SQL构建的“模型”API。 您可以随时通过DSL查询对象上的getQuery()方法访问“model”API

您想要做的一个示例在手册中给出：

https://www.jooq.org/doc/latest/manual/sql-building/sql-statements/dsl-and-non-dsl/

例如，可选择添加联接：

 DSLContext create = DSL.using(configuration); SelectQuery query = create.selectQuery(); query.addFrom(AUTHOR); // Join books only under certain circumstances if (join) query.addJoin(BOOK, BOOK.AUTHOR_ID.equal(AUTHOR.ID)); Result result = query.fetch(); 

或者，选择添加条件/谓词：

 query.addConditions(BOOK.TITLE.like("%Java%")); query.addConditions(BOOK.LANGUAGE_CD.eq("en")); 

更新：鉴于您的意见，这就是您要寻找的：

 // Retrieve search strings from your user input (just an example) String titleSearchString = userInput.get("TITLE"); String languageSearchString = userInput.get("LANGUAGE"); boolean lookingForTitles = titleSearchString != null; boolean lookingForLanguages = languageSearchString != null; // Add only those conditions that the user actually provided: if (lookingForTitles) query.addConditions(BOOK.TITLE.like("%" + titleSearchString + "%")); else if (lookingForLanguages) query.addConditions(BOOK.LANGUAGE_CD.eq(languageSearchString)); 

注意，您还可以使用Field.compare(Comparator, Object)方法：

 // Initialise your dynamic arguments Field field = BOOK.TITLE; Comparator comparator = Comparator.LIKE; String value = "%" + titleSearchString + "%"; // Pass them to the field.compare() method query.addConditions(field.compare(comparator, value)); 

有关更多信息，请考虑org.jooq.SelectQuery Javadoc