Question

这是我的表格表((incrementn 4) 2) => 6 ((incrementn -1) 3) => 2

BUSINESS

表BUSINESSUSERNAME|BUSINESSPASSWORD|BUSINESSNAME| Res1 |123 |Cafe | Res2 |456 |Foodtruck |

USER

表USERNAME|USERPASSWORD|NAME| user1 |123 |mr.1| user2 |234 |mr.2|

FOOD

表FOODID|FOODNAME|FOODPRICE|BUSINESSUSERNAME| 1 |CAKE | 5 |Res1 | 2 |SHAKE | 2 |Res2 | 3 |COLA | 3 |Res1 |

FOOD_RATING

我想得到这张桌子 BUSINESSUSERNAME =＆＃34; Res1＆＃34;

FOODREVIEWID|FOODID|FOORATING|BUSINESSUSERNAME|USERNAME|
1           |2     |3        |Res2            |user1   |
2           |2     |5        |Res2            |user2   |
3           |1     |4        |Res1            |user1   |
4           |3     |1        |Res1            |user1   |

Answer 1

<强>查询

<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.11.1/jquery.min.js"></script>
<script src="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.5/js/bootstrap.min.js"></script>
<link href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.5/css/bootstrap.min.css" rel="stylesheet" />
<div class="content-wrapper">
  <nav class="navbar navbar-default navbar-custom">
    <div class="container-fluid">
      <!-- Brand and toggle get grouped for better mobile display -->
      <div class="navbar-header">
        <button type="button" class="navbar-toggle collapsed" data-toggle="collapse" data-target="#bs-example-navbar-collapse-1" aria-expanded="false"> <span class="sr-only">Toggle navigation</span>
          <span class="icon-bar"></span>
          <span class="icon-bar"></span>
          <span class="icon-bar"></span>

        </button>
        <a class="navbar-brand" href="#">
          <img src="http://placehold.it/150x75/128236/fff?text=Logo" alt="Test Logo" />
        </a>

      </div>
      <!-- Collect the nav links, forms, and other content for toggling -->
      <div class="collapse navbar-collapse" id="bs-example-navbar-collapse-1">
        <ul class="nav navbar-nav navbar-right">
          <li class="dropdown"> <a class="dropdown-toggle" data-toggle="dropdown" href="#">Dropdown<span class="caret"></span></a>

            <ul class="dropdown-menu">
              <li><a href="#">Dropdown 1</a>

              </li>
              <li><a href="#">Dropdown 2</a>

              </li>
            </ul>
          </li>
        </ul>
      </div>
      <!-- /.navbar-collapse -->
    </div>
    <!-- /.container-fluid -->
  </nav>
</div>
<div id="carousel-container">
  <div id="body-carousel" class="carousel slide" data-ride="carousel">
    <div class="carousel-inner" role="listbox">
      <div class="item active">
        <img src="http://placehold.it/2550x500/266080" alt="Chania">
      </div>
      <div class="item">
        <img src="http://placehold.it/2550x500/266080" alt="Chania">
      </div>
      <div class="item">
        <img src="http://placehold.it/2550x500/266080" alt="Flower">
      </div>
      <div class="item">
        <img src="http://placehold.it/2550x500/266080" alt="Flower">
      </div>
    </div>
    <!--Left and Right Buttons-->
    <a class="left carousel-control" href="#body-carousel" role="button" data-slide="prev">
      <span class="glyphicon glyphicon-chevron-left" aria-hidden="true"></span>
      <span class="sr-only">Previous</span>
    </a>
    <a class="right carousel-control" href="#body-carousel" role="button" data-slide="next">
      <span class="glyphicon glyphicon-chevron-right" aria-hidden="true"></span>
      <span class="sr-only">Next</span>
    </a>

  </div>
</div>

<强>输出

select f.foodname, f.foodprice, avg(fr.foodrating)
from food_rating fr
inner join food f
on fr.foodid = f.foodid
group by f.foodname, f.foodprice
;

<强> sqlfiddle

sql连接两个表并计算平均值

1 个答案: