Question

如果唯一的姓名，如何打印姓氏？否则将全名打印为“姓氏，名字”。

示例：在数据库中，您有：Ace Perez，Dan Perez，James Perez和Dan Bond。它应该显示如下内容：

Perez Ace Perez Dan Perez James Bond

它只显示Bond而不是Bond Dan，因为它是一个独特的姓氏。

这是我的代码段：

<?php
$display = "SELECT * FROM main ORDER BY lastName ASC, firstName ASC";
$result = @mysql_query($display)or die(mysql_error());
while($row = mysql_fetch_array($result)){
    $lastName = $row['lastName'];
    $firstName = $row['firstName'];
    $score = $row['score'];
    $totalScore = $row['totalScore'];
    $percentage = ($score/$totalScore)*100;
    echo "<tr>";
        echo "<td align='left'> $lastName </td>";
        echo "<td align='left'> $firstName </td>";
        echo "<td align='left'> $percentage </td>";
    echo "</tr>";
}
    echo "</table>";
?>

编辑：抱歉，我在这里很新。该片段现在应该正常显示！：）

Answer 1

您可以通过计算姓氏上的匹配数来完成此操作。然后将其用于条件select：

select m.lastname, (case when cnt > 1 then m.firstname end) as firstname
from main m join
     (select lastname, count(*) as cnt
      from main
      group by lastname
     ) ml
     on m.lastname = ml.lastname;

Answer 2

如果您有主键，则可以使用CASE和EXISTS的简单查询;

SELECT 
  lastname, 
  CASE WHEN EXISTS 
    ( SELECT 1 FROM test t2 WHERE t1.lastname=t2.lastname AND t1.id<>t2.id )
  THEN firstname ELSE '' END firstname
FROM test t1

An SQLfiddle to test with

仅当姓氏不唯一时才显示名字

2 个答案: