if-statement - 以公式为条件的 if 子句

Question

在给定的查询中，我想给出条件：

if mha(material handling area) has name HB1(mha='HB1') then 
CAST(SUM(minloc) - SUM(noinloc) AS DECIMAL(6,0)) AS '_FREe places' divide with number 2.

怎么可能这么写？我尝试了 IF 子句，但我得到了失败的消息。

SELECT mha, locstat, loctype, SUM(noinloc) '_Kolli', SUM(minloc) '_Plasser',
CAST(SUM(minloc) - SUM(noinloc) AS DECIMAL(6,0)) AS '_Free places''
FROM L30T1
GROUP BY mha, locstat, loctype
ORDER BY mha, locstat, loctype

标签： if-statementconditional-statementsdivide