将case语句重写为if语句

Question

我有这样的ActiveRecord查询。这段代码没有问题。

order(<<-SQL)
  CASE WHEN MAX(disclosures.filed_at) > MAX(short_positions.published_on)
  THEN MAX(disclosures.filed_at)
  ELSE MAX(short_positions.published_on)
  END
SQL

我认为如果用if语句写它会更简单。

order(<<-SQL)
  IF (MAX(disclosures.filed_at) > MAX(short_positions.published_on))
  THEN MAX(disclosures.filed_at)
  ELSE MAX(short_positions.published_on)
  END IF
SQL

但它失败并出现错误：

PG::SyntaxError: ERROR: syntax error at or near "MAX" LINE 1: ... 1) GROUP BY companies.id ORDER BY IF MAX(disclo.

我做错了什么？

整个SQL

"SELECT companies.* FROM \"companies\" INNER JOIN \"stocks\" ON \"stocks\".\"company_id\" = \"companies\".\"id\" INNER JOIN \"disclosures\" ON \"disclosures\".\"company_id\" = \"companies\".\"id\" INNER JOIN \"short_positions\" ON \"short_positions\".\"company_id\" = \"companies\".\"id\" WHERE (stocks.user_id = 1) GROUP BY companies.id  ORDER BY            IF MAX(disclosures.filed_at) > MAX(short_positions.published_on)\n           THEN MAX(disclosures.filed_at)\n           ELSE MAX(short_positions.published_on)\n           END IF\n"

Answer 1

应该有THEN个关键字..

order(<<-SQL)
  IF (MAX(disclosures.filed_at) > MAX(short_positions.published_on)) THEN
    MAX(disclosures.filed_at)
  ELSE
    MAX(short_positions.published_on)
  END IF
SQL

PostgreSQL Control Structures