Update table using stored procedure in SQL Server 2014 - sql-server

Question

I have two tables, please see attached schema, and I have written a stored procedure which is not working. Please help me.
SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
CREATE TABLE [dbo].[countries]
(
[Id] [int] IDENTITY(1,1) NOT NULL,
[Name] [nvarchar](max) NULL,
[Prefix] [nvarchar](max) NULL,
[MinDigits] [int] NULL
) ON [PRIMARY] TEXTIMAGE_ON [PRIMARY]
SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
CREATE TABLE [dbo].[customers]
(
[Id] [int] IDENTITY(1,1) NOT NULL,
[Name] [nvarchar](max) NULL,
[Business] [nvarchar](max) NULL,
[Phone] [nvarchar](max) NULL,
[CountryID] [int] NULL
) ON [PRIMARY] TEXTIMAGE_ON [PRIMARY]
Sample data in the tables:
Id Name Business Phone CountryID
---------------------------------------------------
1 John B&B LLC 001820199202 ***
2 Mike ABC Inc 006192479121 ***
3 Jennifer Coca Cola 0017421 ***
4 Sabine ABC Inc 0091827411 ***
...
Countries:
Id Name Prefix MinDigits
--------------------------------------
1 USA 001 10
2 Australia 0061 11
3 India 0091 9
...
I want to update the CountryID in the customers table based on the countries table.
Result based on above:
Id Name Business Phone CountryID
---------------------------------------------------
1 John B&B LLC 001820199202 1
2 Mike ABC Inc 006192479121 2
3 Jennifer Coca Cola 0017421 ***
4 Sabine ABC Inc 0091827411 3
...
The entry for Jennifer is not updated, since minimum digits are not matching
This is my stored procedure:
SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
ALTER PROCEDURE [dbo].[UpdateCustomer]
AS
BEGIN
SELECT *
INTO #CustomerTable
FROM dbo.customers
DECLARE #Phone NVARCHAR
DECLARE #CountryID INT
DECLARE #Count INT
DECLARE #CustomerID INT
WHILE EXISTS (SELECT * FROM #CustomerTable)
BEGIN
SELECT TOP 1
#Phone = Phone, #CustomerID = Id
FROM
#CustomerTable
IF((SELECT TOP 1 COUNT(*)
FROM countries
WHERE #Phone LIKE Prefix+'%' And LEN(#Phone) <= MinDigits) > 0)
BEGIN
SELECT TOP 1
#CountryID = Id
FROM
countries
WHERE
#Phone LIKE Prefix + '%'
AND LEN(#Phone) <= MinDigits
UPDATE customers
SET CountryID = #CountryID
WHERE Id = #CustomerID
END
DELETE #CustomerTable
WHERE Id = #CustomerID
END
DROP TABLE #CustomerTable
END

Answer 1

You could just do something like this as your entire stored procedure
UPDATE cu
SET cu.CountryId = co.Id
FROM customers cu
JOIN countries co ON cu.phone LIKE co.prefix + '%'
WHERE LEN(cu.phone) >= co.MinDigits

Answer 2

Still, If you want to do it from your SP then define size of #phone variable as
DECLARE #Phone NVARCHAR(30) -- as needed
Its not holding assigned phone number so the update statement is not working.

Answer 3

First of all SQL is set based, so using loop concept is not best idea.
You could use MERGE statement:
MERGE customers c
USING countries cs
ON c.Phone LIKE CONCAT(cs.Prefix, '%')
AND LEN(c.Phone) >= cs.MinDigits
WHEN MATCHED THEN
UPDATE
SET CountryId = cs.Id;
LiveDemo

Answer 4

Use UPDATE FROM
UPDATE customers
SET CountryID = C.Id
FROM
Countries C
WHERE
LEFT(customers.Phone, LEN(C.Prefix)) = C.Prefix AND
LEN(customers.phone) >= C.MinDigits

Answer 5

SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
ALTER PROCEDURE [dbo].[UpdateCustomer]
AS
BEGIN
SELECT *
INTO #CustomerTable
FROM dbo.customers
DECLARE #Phone NVARCHAR(MAX)
DECLARE #CountryID INT
DECLARE #Count INT
DECLARE #CustomerID INT
WHILE EXISTS (SELECT * FROM #CustomerTable)
BEGIN
SELECT TOP 1
#Phone = Phone, #CustomerID = Id
FROM
#CustomerTable
IF((SELECT TOP 1 COUNT(*)
FROM countries
WHERE #Phone LIKE Prefix+'%' And LEN(#Phone) >= MinDigits) > 0)
BEGIN
SELECT TOP 1
#CountryID = Id
FROM
countries
WHERE
#Phone LIKE Prefix + '%'
AND LEN(#Phone) >= MinDigits
UPDATE customers
SET CountryID = #CountryID
WHERE Id = #CustomerID
END
DELETE #CustomerTable
WHERE Id = #CustomerID
END
DROP TABLE #CustomerTable
END