I have a table with three fields, FirstName, LastName and Email. Here's some dummy data: … Now, if I do: … Vitals for Joe is null, as there is a single null field. How do you overcome this behaviour?
mysql> SELECT CONCAT_WS(',','First name','Second name','Last Name')
Union select null, null, null, null, null, null, null from information_schema.tables. for a small database containing three tables. this instruction is used in sql injection I tried it and it worked but I didn't really know how it works can somebody help me...
SELECT CONCAT(login, password) FROM members. Strings without Quotes.
If I have this - tadd is the Address table: … Is there a way to exclude the apt_number if it doesn't exist? I was thinking of: … But it will return only those rows with apt_number...
So_buy+and%28SELECT+1+from%28SELECT+count(*),concat((select+%28SELECT+concat%280X7E%2C0X27%2CDATABASE
A field with a NULL value is a field with no value. If a field in a table is optional, it is possible to insert a new record or update a record without adding a value to this
1 UNION ALL SELECT NULL,concat(0x28,column1,0x3a,column2,0x29) FROM database2.table1--. Error Based.
SQL’s NULL indicates absent data. NULL propagates through expressions and needs distinct comparison operators.
Даже выражение NULL != NULL не будет истинным, ведь нельзя однозначно сравнить одну неизвестность с другой. Кстати, ложным это выражение тоже не будет, потому что при вычислении условий Oracle не ограничивается состояниями ИСТИНА и ЛОЖЬ.