Hi, Only for completeness of the manual, I include the results of perl_dbi_nulls_test.pl using MS Access
Thanks, --------------------------------------------- Using dbi:ODBC:DRIVER={Microsoft Access Driver (*.mdb)};DBQ=D:\Proyecto\STU-La Serena\SinDuplicados_Gustavo 01\Encuestas.mdb;PWD=Chiquita;, db version: 04.00.0000 => Drop table 'dbi__null_test_tmp', if it already exists... => Create table 'dbi__null_test_tmp'... => Insert 4 rows into the table... Inserting values (1, 'Homer') Inserting values (2, NULL) Inserting values (3, 'Marge') Inserting values (4, NULL) => Testing clause style 0: WHERE mycol = ?... Selecting row with Marge Selecting rows with NULL =>Your DBD driver doesn't support the 'rows' method very well. => WHERE clause style 0 returned incorrect results. Non-NULL test rows returned these row ids: 3 The NULL test rows returned these row ids: => Testing clause style 1: WHERE NVL(mycol, '-') = NVL(?, '-')... Selecting row with Marge => Testing clause style 2: WHERE ISNULL(mycol, '-') = ISNULL(?, '-')... Selecting row with Marge => Testing clause style 3: WHERE DECODE(mycol, ?, 1, 0) = 1... Selecting row with Marge => Testing clause style 4: WHERE mycol = ? OR (mycol IS NULL AND ? IS NULL)... Selecting row with Marge Selecting rows with NULL => WHERE clause style 4 is supported. => Testing clause style 5: WHERE mycol = ? OR (mycol IS NULL AND SP_ISNULL(?) = 1)... Selecting row with Marge => Testing clause style 6: WHERE mycol = ? OR (mycol IS NULL AND ? = 1)... Selecting row with Marge Selecting rows with NULL => WHERE clause style 6 is supported. ------------------------------------------------------------------------ 2 styles are supported: Style 4: WHERE mycol = ? OR (mycol IS NULL AND ? IS NULL) Style 6: WHERE mycol = ? OR (mycol IS NULL AND ? = 1) ------------------------------------------------------------------------ --------------------------------------------- Memo Garcia S. memo.garcia...@gmail.com