Master-slave table to get the data, for example students table, table
Scores on the surface of the table band can be A, B, C, D can also be digital
I need to judge scores & gt; What are the students of 90
How should deal with
Because the score is defined as a string type, so there is something wrong with the match,
Can't through! Have to lambda expressions better at, give some directions!

CodePudding user response:

Q&a: why can't I use integral, can only use the money?

CodePudding user response:

Use linq?
Direct the students table. Any (p=& gt; P. scores & gt; 90). The name

CodePudding user response:

Come all the table structure, not what the ABCD,

CodePudding user response:

refer to the second floor shawn_yang response:

use linq?
Direct the students table. Any (p=& gt; P. scores & gt; 90). The name

Scores are of type string, cannot use & gt; 90 judgment

CodePudding user response:

 Where (x=& gt; X.Score.Com pareTo (" 90 ") & gt;=0) 

I do not know if this meets your requirements

CodePudding user response:

The simplest example,
Students table
Student no. Student's name
01 zhang
02 li si
Score
Student no subject result
Chinese 90 01
01 mathematics B
02 Chinese 99
02 math 96
03 language A


Result is a string type, I want to result in language & gt; 90

CodePudding user response:

No, that is similar to compare strings are equal, thank you

CodePudding user response:

Not directly in SQL

CodePudding user response:

refer to the eighth floor Bridge_go response:

not use SQL directly?

Issue is to write not write compatibility, only temporarily use linq, a bag, ha ha

CodePudding user response:

Change result field type, which useful string

CodePudding user response:

references to the tenth floor shawn_yang response:

change result field type, which has a string of

If the deposit is A, B, C, D, ha ha

CodePudding user response:

Let's change the database, you how many points does this represent A, should separate scores and AB two columns

CodePudding user response:

More than 90, the result is A count

CodePudding user response:

Are you sure my way? Might as well try running

CodePudding user response:

 
Int num=0; 
Var query=the from a db in student table 
Join in the db. The b grade table 
On a. student number equals b. Student no. 
.Where int. TryParse (b. result, out num) & amp; & Num> 90 
Select new 
{
Name=a. student's name 
}; 

CodePudding user response:

The

reference 14 floor hands on the keyboard to knock very light response:

are you sure my way? Could try running

Not tried

CodePudding user response:

Why do you want to convert to an int? Estimated when you perform such complains

 
Int num=0; 
Var query=the from a db in student table 
Join in the db. The b grade table 
On a. student number equals b. Student no. 
.Where b.. CompareTo (" 90 ") & gt;=0 
Select new 
{
Name=a. student's name 
}; 

See, because I now are used in this way, as your demand