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



enter image description here



Could someone explain , how it works ?



other values are fine to read



enter image description here



in database column RefNum is a nvarchar column






c# winforms datatable







share|improve this question




















  • 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 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








  • 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















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



enter image description here



Could someone explain , how it works ?



other values are fine to read



enter image description here



in database column RefNum is a nvarchar column






c# winforms datatable







share|improve this question




















  • 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 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








  • 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













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



enter image description here



Could someone explain , how it works ?



other values are fine to read



enter image description here



in database column RefNum is a nvarchar column






c# winforms datatable







share|improve this question















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



enter image description here



Could someone explain , how it works ?



other values are fine to read



enter image description here



in database column RefNum is a nvarchar column






c# winforms datatable




c# winforms datatable






share|improve this question















share|improve this question













share|improve this question




share|improve this question








edited Nov 8 at 13:28

























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. 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








  • 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














  • 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 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








  • 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








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












1 Answer
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0
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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.. :-)






share|improve this answer





















  • 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













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1 Answer
1






active

oldest

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oldest

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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.. :-)






share|improve this answer





















  • 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

















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.. :-)






share|improve this answer





















  • 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















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.. :-)






share|improve this answer












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.. :-)







share|improve this answer












share|improve this answer



share|improve this answer










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




















  • 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




















 

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