Strange problem -- the php function cannot output mysql database query results?

The above function package cannot output any results. In the following example, without function packaging, the output can produce the correct result. Can anyone tell me something? What causes such a result?

The above function package cannot output any results.

The following output can produce correct results without function Packaging

Can anyone give me some advice? What causes such a result?

Reply content:

The above function package cannot output any results.

The following output can produce correct results without function Packaging

Can anyone give me some advice? What causes such a result?

Consider the scope issue, such as database connection?

In the first figure, $ tb_school is not assigned a value in the function.

The second figure produces the correct result. I think the Code has the $ tb_school value defined on it, but it has not been captured.

The correct way of writing the package in the function should be

Function lschool ($ tb_school) {# do something} lschool ('aaaaa') // you can specify parameters as needed.