DataTable select criteria with single quotes and without
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I have a DataTable dt with Column RefNum. There is a row with RefNum = 293
when i try to retrieve value using dt.Select("RefNum = 293")i get no result , but when i wrap number into single quotes dt.Select("RefNum = '293'") i get result
Could someone explain , how it works ?
other values are fine to read
in database column RefNum is a nvarchar column
c# winforms datatable
asked Nov 8 at 13:21
Z.R.T.
1,026511
add a comment |
up vote
-1
down vote
favorite
I have a DataTable dt with Column RefNum. There is a row with RefNum = 293
when i try to retrieve value using dt.Select("RefNum = 293")i get no result , but when i wrap number into single quotes dt.Select("RefNum = '293'") i get result
Could someone explain , how it works ?
other values are fine to read
in database column RefNum is a nvarchar column
c# winforms datatable
asked Nov 8 at 13:21
Z.R.T.
1,026511
2
Sounds like the data type of RefNum is a string type.
– Crowcoder
Nov 8 at 13:23
@Crowcoder RefNum is nvarchar , but so far others values can be read without quotes . How it possible ?
– Z.R.T.
Nov 8 at 13:34
@Z.R.T. Thenvarcharis string in SQL.
– S.Akbari
Nov 8 at 13:35
@S.Akbari agree , but how some values from the same column can be retrieved without quotes but others can't. How can you explain different behavior on the pic ?
– Z.R.T.
Nov 8 at 13:38
1
@Z.R.T. if the behaviour is different, it means the types are different. DataTable objects are .NET objects. The column's type will bestringnotnvarchar. The comparison will follow .NET rules, where comparing objects of different types isfalseby default. In SQL though, one type is implicitly converted into another and the values compared as if they were the same type
– Panagiotis Kanavos
Nov 8 at 14:01
add a comment |
up vote
-1
down vote
favorite
up vote
-1
down vote
favorite
I have a DataTable dt with Column RefNum. There is a row with RefNum = 293
when i try to retrieve value using dt.Select("RefNum = 293")i get no result , but when i wrap number into single quotes dt.Select("RefNum = '293'") i get result
Could someone explain , how it works ?
other values are fine to read
in database column RefNum is a nvarchar column
c# winforms datatable
asked Nov 8 at 13:21
Z.R.T.
1,026511
I have a DataTable dt with Column RefNum. There is a row with RefNum = 293
when i try to retrieve value using dt.Select("RefNum = 293")i get no result , but when i wrap number into single quotes dt.Select("RefNum = '293'") i get result
Could someone explain , how it works ?
other values are fine to read
in database column RefNum is a nvarchar column
c# winforms datatable
c# winforms datatable
asked Nov 8 at 13:21
Z.R.T.
1,026511
asked Nov 8 at 13:21
Z.R.T.
1,026511
edited Nov 8 at 13:28
asked Nov 8 at 13:21
Z.R.T.
1,026511
asked Nov 8 at 13:21
Z.R.T.
1,026511
asked Nov 8 at 13:21
Z.R.T.
1,026511
1,026511
2
Sounds like the data type of RefNum is a string type.
– Crowcoder
Nov 8 at 13:23
@Crowcoder RefNum is nvarchar , but so far others values can be read without quotes . How it possible ?
– Z.R.T.
Nov 8 at 13:34
@Z.R.T. Thenvarcharis string in SQL.
– S.Akbari
Nov 8 at 13:35
@S.Akbari agree , but how some values from the same column can be retrieved without quotes but others can't. How can you explain different behavior on the pic ?
– Z.R.T.
Nov 8 at 13:38
1
@Z.R.T. if the behaviour is different, it means the types are different. DataTable objects are .NET objects. The column's type will bestringnotnvarchar. The comparison will follow .NET rules, where comparing objects of different types isfalseby default. In SQL though, one type is implicitly converted into another and the values compared as if they were the same type
– Panagiotis Kanavos
Nov 8 at 14:01
add a comment |
2
Sounds like the data type of RefNum is a string type.
– Crowcoder
Nov 8 at 13:23
@Crowcoder RefNum is nvarchar , but so far others values can be read without quotes . How it possible ?
– Z.R.T.
Nov 8 at 13:34
@Z.R.T. Thenvarcharis string in SQL.
– S.Akbari
Nov 8 at 13:35
@S.Akbari agree , but how some values from the same column can be retrieved without quotes but others can't. How can you explain different behavior on the pic ?
– Z.R.T.
Nov 8 at 13:38
1
@Z.R.T. if the behaviour is different, it means the types are different. DataTable objects are .NET objects. The column's type will bestringnotnvarchar. The comparison will follow .NET rules, where comparing objects of different types isfalseby default. In SQL though, one type is implicitly converted into another and the values compared as if they were the same type
– Panagiotis Kanavos
Nov 8 at 14:01
2
2
Sounds like the data type of RefNum is a string type.
– Crowcoder
Nov 8 at 13:23
Sounds like the data type of RefNum is a string type.
– Crowcoder
Nov 8 at 13:23
@Crowcoder RefNum is nvarchar , but so far others values can be read without quotes . How it possible ?
– Z.R.T.
Nov 8 at 13:34
@Crowcoder RefNum is nvarchar , but so far others values can be read without quotes . How it possible ?
– Z.R.T.
Nov 8 at 13:34
@Z.R.T. The
nvarchar is string in SQL.– S.Akbari
Nov 8 at 13:35
@Z.R.T. The
nvarchar is string in SQL.– S.Akbari
Nov 8 at 13:35
@S.Akbari agree , but how some values from the same column can be retrieved without quotes but others can't. How can you explain different behavior on the pic ?
– Z.R.T.
Nov 8 at 13:38
@S.Akbari agree , but how some values from the same column can be retrieved without quotes but others can't. How can you explain different behavior on the pic ?
– Z.R.T.
Nov 8 at 13:38
1
1
@Z.R.T. if the behaviour is different, it means the types are different. DataTable objects are .NET objects. The column's type will be
string not nvarchar. The comparison will follow .NET rules, where comparing objects of different types is false by default. In SQL though, one type is implicitly converted into another and the values compared as if they were the same type– Panagiotis Kanavos
Nov 8 at 14:01
@Z.R.T. if the behaviour is different, it means the types are different. DataTable objects are .NET objects. The column's type will be
string not nvarchar. The comparison will follow .NET rules, where comparing objects of different types is false by default. In SQL though, one type is implicitly converted into another and the values compared as if they were the same type– Panagiotis Kanavos
Nov 8 at 14:01
add a comment |
1 Answer
1
active
oldest
votes
up vote
0
down vote
It's very weird that you get results on other tables when searching on string values without quotes. Are you certain these are not numeric columns?
According to docs.microsoft.com/en-us/dotnet/api/system.data.dataview.rowfilter
and www.csharp-examples.net/dataview-rowfilter, filtering on string values/columns requires single quotes.
So I think you better play it safe and use the single quotes.. :-)
answered Nov 8 at 13:45
johey
11410
PS: I cannot see your images, they are blocked by my company's firewall.
– johey
Nov 8 at 13:46
those aren't images, it's the Microsoft documentation site. If you can't read the docs, you can't write or fix code
– Panagiotis Kanavos
Nov 8 at 13:59
add a comment |
1 Answer
1
active
oldest
votes
1 Answer
1
active
oldest
votes
active
oldest
votes
active
oldest
votes
up vote
0
down vote
It's very weird that you get results on other tables when searching on string values without quotes. Are you certain these are not numeric columns?
According to docs.microsoft.com/en-us/dotnet/api/system.data.dataview.rowfilter
and www.csharp-examples.net/dataview-rowfilter, filtering on string values/columns requires single quotes.
So I think you better play it safe and use the single quotes.. :-)
answered Nov 8 at 13:45
johey
11410
PS: I cannot see your images, they are blocked by my company's firewall.
– johey
Nov 8 at 13:46
those aren't images, it's the Microsoft documentation site. If you can't read the docs, you can't write or fix code
– Panagiotis Kanavos
Nov 8 at 13:59
add a comment |
up vote
0
down vote
It's very weird that you get results on other tables when searching on string values without quotes. Are you certain these are not numeric columns?
According to docs.microsoft.com/en-us/dotnet/api/system.data.dataview.rowfilter
and www.csharp-examples.net/dataview-rowfilter, filtering on string values/columns requires single quotes.
So I think you better play it safe and use the single quotes.. :-)
answered Nov 8 at 13:45
johey
11410
PS: I cannot see your images, they are blocked by my company's firewall.
– johey
Nov 8 at 13:46
those aren't images, it's the Microsoft documentation site. If you can't read the docs, you can't write or fix code
– Panagiotis Kanavos
Nov 8 at 13:59
add a comment |
up vote
0
down vote
up vote
0
down vote
It's very weird that you get results on other tables when searching on string values without quotes. Are you certain these are not numeric columns?
According to docs.microsoft.com/en-us/dotnet/api/system.data.dataview.rowfilter
and www.csharp-examples.net/dataview-rowfilter, filtering on string values/columns requires single quotes.
So I think you better play it safe and use the single quotes.. :-)
answered Nov 8 at 13:45
johey
11410
It's very weird that you get results on other tables when searching on string values without quotes. Are you certain these are not numeric columns?
According to docs.microsoft.com/en-us/dotnet/api/system.data.dataview.rowfilter
and www.csharp-examples.net/dataview-rowfilter, filtering on string values/columns requires single quotes.
So I think you better play it safe and use the single quotes.. :-)
answered Nov 8 at 13:45
johey
11410
answered Nov 8 at 13:45
johey
11410
answered Nov 8 at 13:45
johey
11410
answered Nov 8 at 13:45
johey
11410
11410
PS: I cannot see your images, they are blocked by my company's firewall.
– johey
Nov 8 at 13:46
those aren't images, it's the Microsoft documentation site. If you can't read the docs, you can't write or fix code
– Panagiotis Kanavos
Nov 8 at 13:59
add a comment |
PS: I cannot see your images, they are blocked by my company's firewall.
– johey
Nov 8 at 13:46
those aren't images, it's the Microsoft documentation site. If you can't read the docs, you can't write or fix code
– Panagiotis Kanavos
Nov 8 at 13:59
PS: I cannot see your images, they are blocked by my company's firewall.
– johey
Nov 8 at 13:46
PS: I cannot see your images, they are blocked by my company's firewall.
– johey
Nov 8 at 13:46
those aren't images, it's the Microsoft documentation site. If you can't read the docs, you can't write or fix code
– Panagiotis Kanavos
Nov 8 at 13:59
those aren't images, it's the Microsoft documentation site. If you can't read the docs, you can't write or fix code
– Panagiotis Kanavos
Nov 8 at 13:59
add a comment |
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2
Sounds like the data type of RefNum is a string type.
– Crowcoder
Nov 8 at 13:23
@Crowcoder RefNum is nvarchar , but so far others values can be read without quotes . How it possible ?
– Z.R.T.
Nov 8 at 13:34
@Z.R.T. The
nvarcharis string in SQL.– S.Akbari
Nov 8 at 13:35
@S.Akbari agree , but how some values from the same column can be retrieved without quotes but others can't. How can you explain different behavior on the pic ?
– Z.R.T.
Nov 8 at 13:38
1
@Z.R.T. if the behaviour is different, it means the types are different. DataTable objects are .NET objects. The column's type will be
stringnotnvarchar. The comparison will follow .NET rules, where comparing objects of different types isfalseby default. In SQL though, one type is implicitly converted into another and the values compared as if they were the same type– Panagiotis Kanavos
Nov 8 at 14:01