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.
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.
Then in the second table I have select ..., null as opt from... I know that I could have an empty string with '' as
What is the difference between … and … and why does the latter not work?
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...
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 values behave, when making data pre-processing and data
Null (or NULL) is a special marker used in Structured Query Language to indicate that a data value does not exist in the database. Introduced by the creator of the relational database model, E. F. Codd...
The IS NOT NULL condition is used in SQL to test for a non-NULL value.