diff --git a/erpnext/stock/doctype/bin/bin.py b/erpnext/stock/doctype/bin/bin.py
index 48b1cc5..da9c66d 100644
--- a/erpnext/stock/doctype/bin/bin.py
+++ b/erpnext/stock/doctype/bin/bin.py
@@ -4,6 +4,8 @@
 
 import frappe
 from frappe.model.document import Document
+from frappe.query_builder import Case
+from frappe.query_builder.functions import Coalesce, Sum
 from frappe.utils import flt, nowdate
 
 
@@ -19,34 +21,42 @@
 			- flt(self.reserved_qty_for_production) - flt(self.reserved_qty_for_sub_contract))
 
 	def get_first_sle(self):
-		sle = frappe.db.sql("""
-			select * from `tabStock Ledger Entry`
-			where item_code = %s
-			and warehouse = %s
-			order by timestamp(posting_date, posting_time) asc, creation asc
-			limit 1
-		""", (self.item_code, self.warehouse), as_dict=1)
-		return sle and sle[0] or None
+		sle = frappe.qb.DocType("Stock Ledger Entry")
+		first_sle = (
+				frappe.qb.from_(sle)
+					.select("*")
+					.where((sle.item_code == self.item_code) & (sle.warehouse == self.warehouse))
+					.orderby(sle.posting_date, sle.posting_time, sle.creation)
+					.limit(1)
+				).run(as_dict=True)
+
+		return first_sle and first_sle[0] or None
 
 	def update_reserved_qty_for_production(self):
 		'''Update qty reserved for production from Production Item tables
 			in open work orders'''
-		self.reserved_qty_for_production = frappe.db.sql('''
-			SELECT
-				CASE WHEN ifnull(skip_transfer, 0) = 0 THEN
-					SUM(item.required_qty - item.transferred_qty)
-				ELSE
-					SUM(item.required_qty - item.consumed_qty)
-				END
-			FROM `tabWork Order` pro, `tabWork Order Item` item
-			WHERE
-				item.item_code = %s
-				and item.parent = pro.name
-				and pro.docstatus = 1
-				and item.source_warehouse = %s
-				and pro.status not in ("Stopped", "Completed")
-				and (item.required_qty > item.transferred_qty or item.required_qty > item.consumed_qty)
-		''', (self.item_code, self.warehouse))[0][0]
+
+		wo = frappe.qb.DocType("Work Order")
+		wo_item = frappe.qb.DocType("Work Order Item")
+
+		self.reserved_qty_for_production = (
+				frappe.qb
+					.from_(wo)
+					.from_(wo_item)
+					.select(Case()
+							.when(wo.skip_transfer == 0, Sum(wo_item.required_qty - wo_item.transferred_qty))
+							.else_(Sum(wo_item.required_qty - wo_item.consumed_qty))
+						)
+					.where(
+						(wo_item.item_code == self.item_code)
+						& (wo_item.parent == wo.name)
+						& (wo.docstatus == 1)
+						& (wo_item.source_warehouse == self.warehouse)
+						& (wo.status.notin(["Stopped", "Completed"]))
+						& ((wo_item.required_qty > wo_item.transferred_qty)
+							| (wo_item.required_qty > wo_item.consumed_qty))
+					)
+		).run()[0][0] or 0.0
 
 		self.set_projected_qty()
 
@@ -55,36 +65,53 @@
 
 	def update_reserved_qty_for_sub_contracting(self):
 		#reserved qty
-		reserved_qty_for_sub_contract = frappe.db.sql('''
-			select ifnull(sum(itemsup.required_qty),0)
-			from `tabPurchase Order` po, `tabPurchase Order Item Supplied` itemsup
-			where
-				itemsup.rm_item_code = %s
-				and itemsup.parent = po.name
-				and po.docstatus = 1
-				and po.is_subcontracted = 'Yes'
-				and po.status != 'Closed'
-				and po.per_received < 100
-				and itemsup.reserve_warehouse = %s''', (self.item_code, self.warehouse))[0][0]
 
-		#Get Transferred Entries
-		materials_transferred = frappe.db.sql("""
-			select
-				ifnull(sum(CASE WHEN se.is_return = 1 THEN (transfer_qty * -1) ELSE transfer_qty END),0)
-			from
-				`tabStock Entry` se, `tabStock Entry Detail` sed, `tabPurchase Order` po
-			where
-				se.docstatus=1
-				and se.purpose='Send to Subcontractor'
-				and ifnull(se.purchase_order, '') !=''
-				and (sed.item_code = %(item)s or sed.original_item = %(item)s)
-				and se.name = sed.parent
-				and se.purchase_order = po.name
-				and po.docstatus = 1
-				and po.is_subcontracted = 'Yes'
-				and po.status != 'Closed'
-				and po.per_received < 100
-		""", {'item': self.item_code})[0][0]
+		po = frappe.qb.DocType("Purchase Order")
+		supplied_item = frappe.qb.DocType("Purchase Order Item Supplied")
+
+		reserved_qty_for_sub_contract = (
+				frappe.qb
+					.from_(po)
+					.from_(supplied_item)
+					.select(Sum(Coalesce(supplied_item.required_qty, 0)))
+					.where(
+						(supplied_item.rm_item_code == self.item_code)
+						& (po.name == supplied_item.parent)
+						& (po.docstatus == 1)
+						& (po.is_subcontracted == "Yes")
+						& (po.status != "Closed")
+						& (po.per_received < 100)
+						& (supplied_item.reserve_warehouse == self.warehouse)
+					)
+				).run()[0][0] or 0.0
+
+		se = frappe.qb.DocType("Stock Entry")
+		se_item = frappe.qb.DocType("Stock Entry Detail")
+
+		materials_transferred = (
+				frappe.qb
+					.from_(se)
+					.from_(se_item)
+					.from_(po)
+					.select(Sum(
+						Case()
+							.when(se.is_return == 1, se_item.transfer_qty * -1)
+							.else_(se_item.transfer_qty)
+						))
+					.where(
+						(se.docstatus == 1)
+						& (se.purpose == "Send to Subcontractor")
+						& (Coalesce(se.purchase_order, "") != "")
+						& ((se_item.item_code == self.item_code)
+							| (se_item.original_item == self.item_code))
+						& (se.name == se_item.parent)
+						& (po.name == se.purchase_order)
+						& (po.docstatus == 1)
+						& (po.is_subcontracted == "Yes")
+						& (po.status != "Closed")
+						& (po.per_received < 100)
+					)
+				).run()[0][0] or 0.0
 
 		if reserved_qty_for_sub_contract > materials_transferred:
 			reserved_qty_for_sub_contract = reserved_qty_for_sub_contract - materials_transferred
@@ -160,4 +187,4 @@
 		'indented_qty': indented_qty,
 		'planned_qty': planned_qty,
 		'projected_qty': projected_qty
-	})
\ No newline at end of file
+	})