我正在将数据库从mysql迁移到postgres.根据postgres文档,迁移本身还可以.
现在,我正在修复我们特定的mysql查询.
在某些方面,我们现在有这样的事情:
select(%(
SUM(CASE WHEN income THEN value ELSE 0 END) AS rents,
SUM(CASE WHEN not income THEN value ELSE 0 END) AS expenses
))
在mysql中,它是一个总和(if(incomes,value,0))等,并且它按预期工作.
使用PG,它返回一个字符串而不是数字.
我已经检查了数据库,数据类型是正确的.
除了强制转换to_d或to_f之外,我该怎么办?
编辑:完整的查询:
SELECT
SUM(CASE WHEN income THEN value ELSE 0 END) AS rents,
SUM(CASE WHEN not income THEN value ELSE 0 END) AS expenses
FROM "transactions"
WHERE "transactions"."type" IN ('Transaction')
AND "transactions"."user_id" = 1
AND "transactions"."paid" = 't'
AND (transactions.date between '2013-09-01' and '2013-09-30')
LIMIT 1
解决方法:
据我所知,使用.to_f,.to_i或其他任何答案–Rails PostGres适配器似乎坚持认为一切都是String,除非它是ActiveRecord模型.
见:connection.select_value only returns strings in postgres with pg gem
我并不特别赞同这一点,但正如俗话所说,它是“按预期工作”.