PHP if语句带有空查询

Question

I am new to coding. I am trying to get a different text on one of my button if the field is empty. The original code is:

<?php if ( $clpr_options->coupon_code_hide ) {
        $button_text = fl_get_option( 'fl_lbl_show_coupon' );
        $button_text = '<i class="icon-lock"></i>' . $button_text;
        $class .= ' coupon-hidden';
}
     ?>

now I changed it to:

<?php if ( $clpr_options->coupon_code_hide ) {
        $button_text = fl_get_option( 'fl_lbl_show_coupon' );
        $button_text = '<i class="icon-lock"></i>' . $button_text;
        $class .= ' coupon-hidden';
    } else {
        $coupon = get_post_meta( $post->ID, 'clpr_coupon_code', true );
        $coupon == '';
        $button_text = 'Angebot anzeigen';
}
     ?>

however it does not change the content it still shows the first if need some help.

Its not about $button_text being empty, I would like to change the $button_text if there is no content within clpr_coupon_code

Thanks for helping...