How to execute SELECT * LIKE statement with a placeholder in sqlite?

问题

I've got an argument tag and I perfomed this way:

cursor.execute("SELECT * FROM posts WHERE tags LIKE '%?%'", (tag,))

but it doesn't seem to work.
I'm new to sqlite, please tell me how to fix it. Thx !

回答1:

Apply the wildcards to the parameter, not the SQL:

cursor.execute("SELECT * FROM posts WHERE tags LIKE ?", (f'%{tag}%',))

The ? SQL parameter interpolation adds quoting for you, so your query ends up as '%'value'%', which is not valid SQL.

回答2:

Remove the %:

cursor.execute("SELECT * FROM posts WHERE tags LIKE ?", (tag,))

This should format it as you wanted. For example, if tag == 'test' the full query would be:

SELECT * FROM posts WHERE tags LIKE 'test'

来源：https://stackoverflow.com/questions/20904209/how-to-execute-select-like-statement-with-a-placeholder-in-sqlite