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.
The Background I was trying to solve the fourth realistic mission in hackthissite.org, and couldn't figure out exactly what SQL I should inject into the URL to retrieve the list of emails.
Then in the second table I have select ..., null as opt from... I know that I could have an empty string with '' as
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...
In postgres, I'm getting an error when I try to union two tables where one table has a column (Amount) containing double precision data type...
Note: A NULL value is different from a zero value or a field that contains spaces.
Check out this query example: … Is that going to work properly? Table b has no middle name column at all... I figured if that doesn't function right, I could always try this: … Thanks....
What is the difference between … and … and why does the latter not work?
R language supports several null-able values and it is relatively important to understand how these values behave, when making data pre-processing and
NULL is special in SQL. NULL indicates that the data is unknown, inapplicable or even does not