Couldn't use SELECT in including Unicode characters table SQL - sql

Question

I used Bulk Insert to import data from a text:
BULK INSERT dbo.Infosp1 FROM 'D:\test.txt' WITH ( FIELDTERMINATOR =',', ROWTERMINATOR ='\n', DATAFILETYPE='widechar')
This is my 'D:\test.txt'(saved by Endcoding : Unicode ):
BácHồng,Giá,3
BácHồng,Hành,2
BácHồng,Lơxanh,3
BácHồng,Xả,3
BácHồng,Ngao,5
BácHồng,Bắptàu,5
CôHòaBính,Giá,5
CôHòaBính,Càrốt,2
CôHòaBính,Chanh,2
---->This is my table. Click to show image
Why using INSERT shows 0 result??????:
SELECT * FROM dbo.Infosp1 WHERE Khach = 'BácHồng'
or
SELECT * FROM dbo.Infosp1 WHERE Khach = 'CôHòaBính'
---I think that have some problems around convertion data type because save this 'D:\test.txt' by Endcoding : ANSI have some errors like :
BácH?ng, CôH?aBính. In other case, when my field didn't error type i could use SELECT to show all results. I want have a solve could make it work.

Answer 1

Try prepending N to unicode string literals in SQL Server:
SELECT * FROM dbo.Infosp1 WHERE Khach = N'BácHồng'
and
SELECT * FROM dbo.Infosp1 WHERE Khach = N'CôHòaBính'
Example:
create table Infosp1 (Khach nvarchar(64), FirstName nvarchar(64), SomeNumber int)
insert into Infosp1 values
(N'BácHồng',N'Giá',3)
,(N'BácHồng',N'Hành',2)
,(N'BácHồng',N'Lơxanh',3)
,(N'BácHồng',N'Xả',3)
,(N'BácHồng',N'Ngao',5)
,(N'BácHồng',N'Bắptàu',5)
,(N'CôHòaBính',N'Giá',5)
,(N'CôHòaBính',N'Càrốt',2)
,(N'CôHòaBính',N'Chanh',2)
SELECT 'WithN' as WithOrWithoutN, * FROM dbo.Infosp1 WHERE Khach = N'BácHồng'
union all
SELECT 'WithoutN',* FROM dbo.Infosp1 WHERE Khach = 'BácHồng'
union all
SELECT 'WithN', * FROM dbo.Infosp1 WHERE Khach = N'CôHòaBính'
union all
SELECT 'WithoutN',* FROM dbo.Infosp1 WHERE Khach = 'CôHòaBính'
rextester demo: http://rextester.com/WSNNX6950
returns:
+----------------+-----------+-----------+------------+
| WithOrWithoutN | Khach | FirstName | SomeNumber |
+----------------+-----------+-----------+------------+
| WithN | BácHồng | Giá | 3 |
| WithN | BácHồng | Hành | 2 |
| WithN | BácHồng | Lơxanh | 3 |
| WithN | BácHồng | Xả | 3 |
| WithN | BácHồng | Ngao | 5 |
| WithN | BácHồng | Bắptàu | 5 |
| WithN | CôHòaBính | Giá | 5 |
| WithN | CôHòaBính | Càrốt | 2 |
| WithN | CôHòaBính | Chanh | 2 |
| WithoutN | CôHòaBính | Giá | 5 |
| WithoutN | CôHòaBính | Càrốt | 2 |
| WithoutN | CôHòaBính | Chanh | 2 |
+----------------+-----------+-----------+------------+