SQLite如果列存在
问题描述：
我想知道是否有一个很好的IF NOT EXISTS检查SQLite列和索引，或者我需要带回整个数据库模式并验证？
I was wondering if there is a nice IF NOT EXISTS for checking columns and indexes in SQLite, or do I need to bring back the entire database schema and validate against that?
答
是的，sqlite支持以下语法： CREATE INDEX IF NOT EXISTS ...
Yes the following syntax is supported in sqlite: CREATE INDEX IF NOT EXISTS ...
要检查列的存在，你可以简单地尝试做一些 SELECT col from TABLE 。如果它不返回错误，您的表包含 col 。
To check existence of a column you could simply try to do something like SELECT col from TABLE. If it does not return an error your table contains col.