CreateFunction Like

SUAT SUPHI 61

Hi,

I need an example about CreateFunction for like

Could you give me an example ?

https://learn.microsoft.com/en-us/dotnet/standard/data/sqlite/user-defined-functions

2 answers

Bruce (SqlWork.com) 69,806 Reputation points

2023-01-15T18:18:36.6166667+00:00
connection.CreateFunction( "like", (string a, string b) => a == b);
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SUAT SUPHI 61 Reputation points

2023-01-15T22:46:55.52+00:00

thank you Bruce

can I replace a or b s strings ?

I guess I have to use DbFunctionsExtensions.Like but I don know how it use

Qing Guo - MSFT 896 Reputation points Microsoft Vendor

2023-01-16T03:13:42.7066667+00:00

Hi @SUAT SUPHI ,

Do you want to use DbFunctionsExtensions.Like as below?

.Where(e => EF.Functions.Like(x.SomeColumn, "filter.Keyword"))

SUAT SUPHI 61 Reputation points

2023-01-16T11:55:09.6966667+00:00

Thank you

but I wanna use it in createfunction

there is an console app here:

_connection.CreateFunction("Like ", ...........................

SELECT * FROM Product where Replace(Name,'i','') like Replace('%ilk%','i','');

https://github.com/suatsuphi/ConsoleToLower/blob/master/ConsoleToLower/Program.cs

protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder) { _connection.CreateCollation("NOCASE", (x, y) => string.Compare(x, y, ignoreCase: true)); _connection.CreateFunction("upper", (string x) => x.ToUpper(), isDeterministic: true); _connection.CreateFunction("lower", (string x) => x.ToLower(), isDeterministic: true); //_connection.CreateFunction("like", optionsBuilder.UseSqlite(_connection); }
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Jack J Jun 24,631 Reputation points Microsoft Vendor

2023-01-19T09:29:28.83+00:00
@SUAT SUPHI, Welcome to Microsoft Q&A, if you want to make the function to replace string.

You could try the following code.

_connection.CreateFunction("likeit",(string x,string y)=> y, isDeterministic: true);

Then, you could call it in the commandtext like the following:

string sql = "select * from Posts where Title==likeit('i','h')";

The result is equal to

select * from Posts where Title='h'.

Note: I suggest that you don't use the like keyword in the sql because it already has some definitions.

Hope my solution could help you.

Best Regards,

Jack

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