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.
Then in the second table I have select ..., null as opt from... I know that I could have an empty string with '' as
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...
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.
I have noticed a number of queries at work and on SO are using limitations in the form: … Is there a particular reason why people do that and not the more terse … Is it a legacy or a performance issue?
Does the mysql UNION and UNION ALL operator always remove rows that have a NULL in them? I am doing a UNION of two SELECT statements - one of which may return a row with a NULL in it.
Note: A NULL value is different from a zero value or a field that contains spaces.
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...
R language supports several null-able values and it is relatively important to understand how these values behave, when making data pre-processing and
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)...