pandas equivalent of np.where

Try: (df[‘A’] + df[‘B’]).where((df[‘A’] < 0) | (df[‘B’] > 0), df[‘A’] / df[‘B’]) The difference between the numpy where and DataFrame where is that the default values are supplied by the DataFrame that the where method is being called on (docs). I.e. np.where(m, A, B) is roughly equivalent to A.where(m, B) If you wanted a … Read more

SQLSTATE[42S22]: Column not found: 1054 Unknown column – Laravel

You have configured the auth.php and used members table for authentication but there is no user_email field in the members table so, Laravel says SQLSTATE[42S22]: Column not found: 1054 Unknown column ‘user_email’ in ‘where clause’ (SQL: select * from members where user_email = ? limit 1) (Bindings: array ( 0 => ‘test@hotmail.com’, )) Because, it … Read more

MySQL Select last 7 days

The WHERE clause is misplaced, it has to follow the table references and JOIN operations. Something like this: FROM tartikel p1 JOIN tartikelpict p2 ON p1.kArtikel = p2.kArtikel AND p2.nNr = 1 WHERE p1.dErstellt >= DATE(NOW() – INTERVAL 7 DAY) ORDER BY p1.kArtikel DESC EDIT (three plus years later)    The above essentially answers the question … Read more

Is a JOIN faster than a WHERE?

Theoretically, no, it shouldn’t be any faster. The query optimizer should be able to generate an identical execution plan. However, some database engines can produce better execution plans for one of them (not likely to happen for such a simple query but for complex enough ones). You should test both and see (on your database … Read more