SQLite：如何通过部分列匹配进行JOIN？

Question

I'm trying to get all the data from the Documents table where the list of Box numbers in the BoxNumber table is somewhere within a string in a column in the Documents table.

The problem I'm running into right now is that none of the example code with '%' + ColumnName + '%' or '%' || ColumnName || '%' '%' + ColumnName + '%' or '%' || ColumnName || '%' '%' + ColumnName + '%' or '%' || ColumnName || '%' will work. it'll just return either nothing, or all the data in the Documents table.

Example code:

This returns all data in the Documents table instead of all data containing a document number similar to the list in the BoxNumbers table.

SELECT * 
from [Documents]
LEFT JOIN BoxNumbers ON 
BoxNumbers.BoxNum like '%' + Documents.DocNum + '%'

Anyone know why this isn't working? It seems like it's worked for people using MySQL and SQL server, so is this just another quirk of SQLite?

Answer 1

The SQLite concatenation operator is not + but || , so change to this:

SELECT * 
from [Documents]
INNER JOIN BoxNumbers ON 
BoxNumbers.BoxNum like '%' || Documents.DocNum || '%'

with INNER join.