select a,b,null,null from table1 union select null,null,c,d from table2 union select null,null,null,null,e,f from table3.
I read in a book (Thinking in Java by Bruce Eckel, 4th edition, page 47) that null is equal to '\u000'. And then I was wondering what exactly does '\u000' really mean.
Then in the second table I have select ..., null as opt from... I know that I could have an empty string with '' as
I have a Postgres table with a string column carrying numeric values. I need to convert these strings to numbers for math, but I need both NULL values as well as empty strings to be interpreted as 0. I can...
So which is it? Set NULL value to 0, or set 0 values to NULL?
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
The null character (also null terminator or null byte), abbreviated NUL or NULL, is a control character with the value zero. It is present in many character sets, including ISO/IEC 646 (or ASCII)...
Number of null-s on change between passed and failed queries is the one attacker looks for.
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...
SQL’s NULL indicates absent data. NULL propagates through expressions and needs distinct comparison operators.