php - 如何计算所选表中具有空字段的所有记录

Question

假设我有四个个表，我只需选择3个表，其数据库名为Records

Records
1.Cases
2.Ballistics
3.Chem
4.Accounts

Cases
id|year|Natureofcase |
0 |    |Repact 1901a |
1 |2003|Repact 1907b |
3 |2004|Repact 1902  |

Ballistics
id|year|Name     |Type  |
0 |2003|         |a-101 | 
1 |    |Silver-A |a-202 |
3 |2005|Red Cap  |      |

Chem
id|year|Identified   |
0 |    |H20+C20      |
1 |2001|Am           |
3 |2009|             |  

所以我们有 6 行包含空表。 我想使用 PHP 显示总和 6。谢谢。任何意见/答案/建议将不胜感激。

Answer 1

请尝试一下

SELECT 
   (SELECT COUNT(*) FROM Cases WHERE year = '' OR Natureofcase = '') +
   (SELECT COUNT(*) FROM Ballistics WHERE year ='' OR Name='' OR Type='') +
   (SELECT COUNT(*) FROM Chem WHERE year='' OR Identified='')
AS total_empty