To raise knowledge, to rise Knowledge: thinkphp framework where conditions query MySQL database If a field is empty

Code abuse me times, I to code such as first love ~

Problem:

Querying a field app_date whether the data is null, the normal way we do this is:

$map Array (' eq ', ' null '); $data M ("Info") , Field ("*"), where ($map), select ()

Use echo M ("Info")->getlastsql (); Print SQL statements as follows:

SELECT ' id ', ' name ', ' create_time ', ' app_data ' from ' info ' WHERE ' app_data ' = ' NULL '

But the printed SQL statement is not what I want to do, hair, modify the test, modify the test, always do not reach the correct SQL statement I want, the following is correct:

SELECT ' id ', ' name ', ' create_time ', ' app_data ' from ' info ' WHERE ' app_data ' is NULL

The solution is always there, how to do, look at the document, go through the document in At the bottom you see something like this :

Correct judgment Method:

$map Array (' EXP ', ' is NULL ');; $data = M ("Info"), Field ("*"), where ($map), select ()

To print the SQL statement:

SELECT ' id ', ' name ', ' create_time ', ' app_data ' from ' info ' WHERE ' app_data ' is NULL

Perfect ~~~~~~~

To raise knowledge, to rise Knowledge: thinkphp framework where conditions query MySQL database If a field is empty