I have developed a query, and in the results for the first three columns I get NULL. How can I replace it with 0?
select a,b,null,null from table1 union select null,null,c,d from table2 union select null,null,null,null,e,f
Then in the second table I have select ..., null as opt from... I know that I could have an empty string with '' as opt however, I don't want an empty string, I really do need it to be null.
SELECT COUNT(*), 'null_tally' AS narrative FROM us WHERE a IS NULL UNION SELECT COUNT(*), 'not_null_tally' AS narrative FROM us
What is the difference between … and … and why does the latter not work?
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.
-999.9+union+all+select+%27R3DM0V3_hvj_injection',null%2CNULL%2CNULL%2CNULL%2CNULL%2CNULL
union all select null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null
Note: A NULL value is different from a zero value or a field that contains spaces.
R language supports several null-able values and it is relatively important to understand how these