Question

我正在编写需要三列的SQL查询。其中之一是COUNT，它是多个子查询的结果。我在FROM ..行收到错误消息“ SQL命令未正确结束”。我想这是一个语法错误，与上面的COUNT部分有关。我在做错事时可以得到一些帮助吗？

SELECT STUDENTS.NAME AS NAME,
      ADDRESS.CITY AS CITY,
      COUNT(*) AS MY_COUNT FROM (SELECT MYSTATE FROM SOME_TABLE
                                  WHERE SOME_ATTRIBUTE IN 
                                                   (SELECT SUBQUERY_2 = 
                                                                     (SUBQUERY_3))) 
FROM MYSCHEMA.ADDRESS ADDRESS --Error: SQL command not properly ended
  INNER JOIN SCHEMA.STUDENTS STUDENTS
  ON ADDRESS.ID=STUDENTS.ID

GROUP BY STUDENTS.NAME, STUDENTS.CITY

Answer 1

我想您的第一个FROM与您要依赖的表/查询有某种关系。如果是这样，那么这样做是错误的形式。您需要将其转换为标量子查询：

SELECT STUDENTS.NAME AS NAME,
      ADDRESS.CITY AS CITY,
      (SELECT COUNT(*) FROM (...) WHERE ...) AS MY_COUNT  
FROM MYSCHEMA.ADDRESS ADDRESS 
...

从您提供给我们的内容中，无法猜测需要放在内部FROM / WHERE内部的内容。这是因为“其中之一是COUNT，它是多个子查询的结果”对于解释要尝试实现（计数）准确的内容来说，这是毫无希望的。因此，如果您需要帮助，请详细说明 HOW “ COUNT是多个子查询的结果”。

Answer 2

现在尝试此解决方案：

SELECT STUDENTS.NAME AS NAME,ADDRESS.CITY AS CITY,
(SELECT COUNT(*) FROM SOME_TABLE WHERE SOME_ATTRIBUTE IN (SELECT SUBQUERY_2 = (SUBQUERY_3))) AS MY_COUNT 
FROM MYSCHEMA.ADDRESS ADDRESS 
INNER JOIN SCHEMA.STUDENTS STUDENTS  ON ADDRESS.ID=STUDENTS.ID
GROUP BY STUDENTS.NAME, STUDENTS.CITY

具有包含子查询的属性的SQL查询中的语法错误

2 个答案: