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 have developed a query, and in the results for the first three columns I get NULL. How can I replace it with 0?
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.
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...
What is the difference between … and … and why does the latter not work?
I need a list with three columns. column 1st and 3rd having values while 2nd as null. Can I do it through HQL query? I need something like this: …
How can I run a MySQL query that selects everything that is not null? It would be something like … Do I just remove the all and go..?
How can I count null values as 1 value and use distinct to avoid count repeated values? I'm learning advanced SQL, they want me these requirements for all the solutions: Try to minimize the number of subqueries you need to solve the query.
Note: A NULL value is different from a zero value or a field that contains spaces. A field with a NULL value is one that has been left
Union select null, null, null, null, null, null -- test all nulls --*/ ). A.