从 Node.js 中的 SQLite 数据库中的不同表中获取所有数据

Question

Is it a way to get all data from a database?

So far I accomplished to get all data from a table:

router.get('/', function (req, res, next) {
  db.serialize(function () {
    db.all('SELECT id, name, surname FROM Table1', function (
      err,
      rows
    ) {
      return res.send(rows);
    });
  });

  db.close();
});

but if there are more tables, Table1 , Table2 and Table3 for example.

Trying to put all the queries in the db.all call doesn't seem to work.

 router.get('/', function (req, res, next) {
      db.serialize(function () {
        db.all('SELECT id, name, surname FROM Table1, SELECT date, city FROM Table2, SELECT person, year FROM Table3', function (
          err,
          rows
        ) {
          return res.send(rows);
        });
      });
    
      db.close();
    });

UPDATE

these are the tables, how can I get all their data and send it into front-end? that's what I want to do.

I would rather want to have them like separate tables in the front-end where the call is fetched like this:

callAPI() {
    fetch('http://localhost:9000/testAPI')
      .then((res) => res.text())
      .then((res) => this.setState({ apiResponse: res }));
  }

is there a way to send all these tables?

Answer 1

Provided that all your tables have the same columns or at-least the output can be aliased into same column names (maybe put nulls if the column is not in one of the tables), you can make use of UNION

eg:

SELECT id, name FROM table1 
 UNION 
   SELECT id, name FROM table2
 UNION 
   SELECT myid as id, test as name FROM table3

This way you can append all such tables into a single output table. Also if you want it to aggregate through code, you can use the below query to get all table names and work with each table:

SELECT name FROM my_db.sqlite_master WHERE type='table';