How to use a select query in the where clause in mysql?

Question

I am trying to retrieve everything from a table where the invoiceNo is distinct.So here is what I tried.

SELECT * FROM  `selected_items` WHERE 'invoiceNo' IN 
(SELECT DISTINCT(invoiceNo) AS invoiceNo FROM selected_items`);

When I try this in php myadmin I get the following warning with no output.

You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '' at line 2.

And when I run my php script from my android app it returns nothing.Is there a place where I can check my query like php code checker.

I am new to programming so any help and suggestion is welcome.Thank you :)

Answer 1

Change this:

SELECT * FROM  `selected_items` WHERE 'invoiceNo' IN 
(SELECT DISTINCT(invoiceNo) AS invoiceNo FROM selected_items`);

To

 SELECT * FROM  `selected_items` WHERE invoiceNo IN (SELECT DISTINCT(invoiceNo) AS invoiceNo FROM selected_items ) GROUP BY invoiceNo

Because invoiceNo is a column name, you should not be using the quotes on it, either leave it like it is or use backticks.

Answer 2

正如Saty在评论中已经提到的那样：您可能的意思是：

SELECT * FROM selected_items GROUP BY invoiceNo;

Answer 3

Remove the "`" symbol end of your code and remove single quotes in field name because values only need single quotes.

Like this:

"SELECT * FROM  `selected_items` WHERE invoiceNo IN 
(SELECT DISTINCT(invoiceNo) AS invoiceNo FROM selected_items);"

Answer 4

Remove the "`" symbol end of your code and

You try this one....

SELECT * FROM `selected_items` WHERE `invoiceNo` IN (SELECT DISTINCT(invoiceNo) AS invoiceNo FROM selected_items);