* Andre Matos > I am performing a SELECT and I am getting 0 rows when I run the SELECT > direct in the MySQL database and getting 1 when I run using PHP. > This is my > select: > > SELECT * FROM scan WHERE TimePointID = 3 AND ScanQCResult = 'n' AND > (ScanStatusID < 90 OR ScanStatusID > 98);
Looks ok. > I realized latter analyzing this select that I made a mistake using OR at > this point: (ScanStatusID < 90 OR ScanStatusID > 98), it should be "AND". Are you sure about that? > However, in both cases, I am still getting 0 rows from the database, which > is correct. > > My problem is using the PHP to run the SELECT, if I use OR using > the PHP, I > got 1 as a result, and if I use AND I got 0 as a result. This is correct, if you have one record with ScanStatusID in the range 90-98. > Is anyone can tell me what is going on? You seem to be misinterpreting how logical expressions work. A SQL select statement is a description of the (sub-)set of data you wish to retrieve from the database. This description often includes a WHERE clause, describing wanted records, which again often includes a logical expression. The expression is built up by operands and operators. The logical operators relevant in SQL is AND, OR and NOT. NOT is a negation, this operator takes one operand, the the result is the opposite of the operand. NOT true is false, and NOT false is true. The other two operators, AND and OR, need two operands, one on each side. For the AND operator, BOTH sides of the operator must be true for this part of the expression to be true. For the OR operator, ANY of the sides of the operator must be true for that part of the expression to be true. So, for your expression above, you can not say ...ScanStatusID < 90 AND ScanStatusID > 98..., because ScanStatusID can not be below 90 AND above 98. ScanStatusID is a single number, it can be below 90 OR above 98. Not both at the same time. -- Roger -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe: http://lists.mysql.com/[EMAIL PROTECTED]
