我有一个带有脚本的php页面，它根据所选的“年”显示行。这是由$\u get from url字符串执行的，然后在mysql查询中使用一个变量。 $jID = (int)$_GET['id']; ```
SELECT lh., c.country AS c, c.flag, MAX(countv) countv, MAX(counta) counta
FROM (
SELECT vg.vertrekluchthaven AS code, count() as countv, 0 as counta
FROM tbl_vluchtgegevens vg
WHERE year(vg.vertrekdatum2) = '$jID'
GROUP BY vg.vertrekluchthaven

UNION  

  SELECT vg.aankomstluchthaven AS code, 0 as countv, count(*) as counta
  FROM tbl_vluchtgegevens vg  
  WHERE year(vg.vertrekdatum2) = '$jID'
  GROUP BY vg.aankomstluchthaven

) vg

LEFT JOIN tbl_luchthaven lh
ON lh.luchthavenID = vg.code

LEFT JOIN tbl_countries c
ON lh.countryID = c.countryID

GROUP BY vg.code
ORDER BY lh.luchthavencode;
``` ?id=2018 可能产生

| Code | Name                       | # Arrival | # Depart |
| AMS  | Amsterdam                  | 3         | 2        |
| MSP  | Minneapolis                | 5         | 5        |
| TLL  | Tallinn                    | 1         | 1        |

我还想对所有行进行计数，然后在循环中使用粗体和红色（或其他格式）的条件，如果整个表的计数小于等于0，那么现在小于等于 $_GET 价值观。
有没有一种方法可以在其中添加一个子查询，将联合查询的总计数作为一列提供给我，例如：

| Code | Name                       | # Arrival | # Depart | # Total |
| AMS  | Amsterdam                  | 3         | 2        | 64      |
| MSP  | Minneapolis                | 5         | 5        | 122     |
| TLL  | Tallinn                    | 1         | 1        | 1       |

FROM (
          SELECT vg.vertrekluchthaven AS code, count(*) as countv, 0 as counta
          FROM tbl_vluchtgegevens vg
          WHERE year(vg.vertrekdatum2) <= '$jID'
          GROUP BY vg.vertrekluchthaven

        UNION  

          SELECT vg.aankomstluchthaven AS code, 0 as countv, count(*) as counta
          FROM tbl_vluchtgegevens vg  
          WHERE year(vg.vertrekdatum2) <= '$jID'
          GROUP BY vg.aankomstluchthaven
       ) vg

然后我就可以用 if ($row['totalcount'] >0) /php中用于条件格式的else子句。