MATCH（字段1，字段2）和MATCH（字段1）或MATCH（字段2）之间的区别

Question

Is there a difference in results between the two below queries?

SELECT *
FROM table1, table2
WHERE
    ( MATCH(table1.row1) AGAINST('searchstring' IN BOOLEAN MODE) )
    OR
    ( MATCH(table2.row2) AGAINST('searchstring' IN BOOLEAN MODE) )


SELECT *
FROM table1, table2
WHERE
    ( MATCH(table1.row1, table2.row2) AGAINST('searchstring' IN BOOLEAN MODE) )

I prefer the first approach, as that makes it more easy for me to implement ranking criteria for each field.

Answer 1

Yes, the second query is an error.

The MATCH() function's arguments must be all the columns for which one fulltext index is defined.

But indexes cannot be defined over multiple tables. Therefore an exppression like MATCH(table1.row1, table2.row2) can't work, because it references columns from two different tables.

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If you reference only columns from the same table, then it's okay to put multiple columns in a MATCH() function. In fact, it's mandatory if the fulltext index was defined over multiple columns. Note that above, I said that the function's arguments must be all columns for a fulltext index.