Hanafi
The sources give no view for it here.
الصلاة على القبر
هل تجوز الصلاة على قبر الميت؟
Each school’s answer
In our wordsHanafi
Not stated in the sources
Maliki
Not stated in the sources
Shafi'i
Not stated in the sources
Hanbali
Not stated in the sources
The texts
م - الصَّلاَةُ عَلَى الْقَبْرِ: ٢٣ - ذَهَبَ جُمْهُورُ الْفُقَهَاءِ إلَى جَوَازِ الصَّلاَةِ عَلَى قَبْرِ الْمَيِّتِ فِي الْجُمْلَةِ، عَلَى تَفْصِيلٍ وَخِلاَفٍ يُنْظَرُ فِي مُصْطَلَحِ: (جَنَائِزُ ف ٣٧) .
«الموسوعة الفقهية الكويتية» (Kuwait) entry «قبر» vol. 32 p. 256
From the schools’ own books
Maliki
The sources give no view for it here.
Shafi'i
The sources give no view for it here.
Hanbali
The sources give no view for it here.
What is «in our words» is our standard wording; the books’ texts stay as they are.