text: export function exercise1() {
      return [
          {
              query: `CREATE OR REPLACE VIEW TRACKS_FULL_DATA AS SELECT
                          t.id AS track_id,
                          t.title AS track_title,
                          a.title AS album_title,
                          u.email AS user_mail,
                          c.name AS country_name
                      FROM
                          tracks AS t,
                          users AS u,
                          country AS c,
                          albums AS a 
                      WHERE  
                          t.albumid = a.id
                          AND t.userid = u.id
                          AND u.countrycode = c.code`,
              type: 'RAW'
          }
      ];
  }
  export function exercise2() {
      return [
          {
              query: `SELECT
                          a.title
                      FROM 
                          albums AS a,
                          users AS u,
                          country AS c 
                      WHERE 
                          a.genre = 'ROCK' 
                          AND a.userid = u.id
                          AND u.countrycode = c.code
                          AND c.name = 'PERU'`,
              type: 'SELECT'
          }
          
      ];
  }
  export function exercise3() {
      return [
          {
              query: `UPDATE
                          tracks t,
                          users u
                      SET
                          t.artist = u.name
                      WHERE
                          t.artist IS NULL
                          AND t.userid = u.id`,
              type: 'UPDATE'
          }
          
  ];
  }
  export function exercise4() {
      return [
          {
              query: `UPDATE
                          albums
                      SET
                          albums.status = 0
                      WHERE
                          albums.id NOT IN (
                              SELECT
                                  albumid
                              FROM
                                  tracks
                          )`,
              type: 'UPDATE'
          },
          {
              query: `SELECT * FROM albums WHERE status = 0`,
              type: 'SELECT'
          }
          
          
      ];
  }
  export function exercise5() {
      return [
          {
              query:  `UPDATE
                          users as u
                      SET
                          u.status = 0
                      WHERE
                          NOT EXISTS (
                              SELECT
                                  1
                              FROM
                                  tracks AS t,
                                  albums AS a
                              WHERE
                                  t.userid = u.id
                                  AND a.userid = u.id
                          )`,
              type: 'UPDATE'
          },
          {
              query: `SELECT
                          u.*
                      FROM
                          users AS u
                      WHERE
                          NOT EXISTS (
                          SELECT
                              1
                          FROM
                              tracks AS t,
                              albums AS a
                          WHERE
                              t.userid = u.id
                              AND a.userid = u.id
                      )`,
              type: 'SELECT'
          }
      ];
  }
  export function exercise6() {
      return [
          {
              query: `SELECT 
                          t.*
                      FROM
                          tracks as t,
                          albums as a
                      WHERE
                          t.genre <> a.genre`,
              type: 'SELECT'
          }
          
      ];
  }
  