SQL statement error

SQL statement error MySQL

$ Query = "select * from a where 'Z' = '$ url [query] 'limit"; if you write this statement, the following error occurs: Warning: mysql_fetch_array (): supplied argument is not a valid MySQL result resource in $ query = "select * from a where 'Z' = '$ url [query]'; but this works. why?

Reply to discussion (solution)

$ Query = "select * from a where 'Z' = '". $ url ['query']. "'limit 0, 10 ";

Echo mysql_error ();

I am a newbie, but I learned this troubleshooting method after watching the php video of Chuanzhi podcast. I printed $ query (echo) first, then, put the printed result into the mysql black window to see if it can get the result. If not, check the error message and modify it as appropriate.
According to your error message, the result set $ res = mysql_query ($ SQL, $ conn) was not obtained successfully.

Determine whether there is a value