code: func checkUniqueKeyIncludePartKey(partCols []*expression.Column, idxCols []*ast.IndexColName) bool {
  	for _, partCol := range partCols {
  		if !findColumnInIndexCols(partCol, idxCols) {
  			return false
  		}
  	}
  	return true
  }
docs: // checkUniqueKeyIncludePartKey checks that the partitioning key is included in the constraint.