mysql - Mysql 在第二列不返回值时的情况

Question

它只返回 EIA 的值而不返回 EIA 2

(
  case 
   when tc.name = 'EIA' then tor.value else null 
  end
) as EIA, 
(
  case 
   when tc.name = 'EIA 2' then tor.value else null 
  end
) as EIA2

这是这个表结构

测试执行的 Tor 值环评、环评2正、正

ID Name  EIA      EIA 2
1  John  POSITIVE no values??

Answer 1

试试这个:

(
  CASE 
   WHEN tc.name IS NULL THEN '' WHEN tc.name = 'EIA' THEN tor.value
  END
) as EIA, 
(
  CASE 
   WHEN tc.name IS NULL THEN '' WHEN tc.name = 'EIA 2' THEN tor.value
  END
) as EIA2