错误：“-”或附近的语法错误-SUBQUERY

Question

目标

我有应减去值的两个表，但错误返回我子查询，因为应该发生减法如下（ TABLE1 。 COLUMN1 - TABLE2 。 COLUMN1 ），依此类推。

询问

SELECT COUNT(*) hostname - CAST(tb_getCountSRVS.srvs AS int)
FROM tb_get_gap
LEFT JOIN tb_getCountSRVS
  ON tb_get_gap.customer = tb_getCountSRVS.cust_code
WHERE tb_getCountSRVS.customer in (
  SELECT customer
  FROM tb_getCountSRVS
) AND tb_get_gap.exception = 'NO'
GROUP BY tb_get_gap.customer
ORDER BY tb_get_gap.customer ASC

产量

> [Error] Script lines: 1-5 --------------------------
 ERROR: syntax error at or near "-"
 Line: 1 

Answer 1

语法错误是由于以下事实导致的：在主SELECT ，您给COUNT(*)赋予了别名（ hostname COUNT(*) ，然后您尝试进行减法。
您应该按如下所示更正查询的第一行：

SELECT (COUNT(*) - CAST(tb_getCountSRVS.srvs AS int)) AS hostname