Could you please explain the output of the function

Question

0.00/5 (No votes)

See more:

CREATE FUNCTION [dbo].[udf_GenerateWhereQuery]
(@logic char(10), @Field varchar(250),@Operator varchar(100), @Value Nvarchar(max), @DataType varchar(100) ,@RowNum int)
RETURNS NVARCHAR(MAX)
AS
BEGIN
DECLARE @WhereQuery NVarchar(MAX),@SQLOperator NVARCHAR(MAX)
SET @SQLOperator = CASE
WHEN @DataType = 'String'
THEN CASE
WHEN @Operator = 'startswith'
THEN @Field + ' LIKE ' + 'N''' + @Value + '%' + ''''
WHEN @Operator = 'endswith'
THEN @Field + ' LIKE ' + 'N''' + '%' + @Value +''''
WHEN @Operator = 'eq'
THEN @Field + '=' + 'N''' + @Value + ''''
WHEN @Operator = 'neq'
THEN 'ISNULL(' + @Field + ','''')' + '<>' + 'N''' + @Value + ''''
WHEN @Operator='contains'
THEN @Field + ' LIKE ' + 'N'''+'%'+@Value + '%' + ''''
WHEN @Operator ='does not contain' OR @Operator ='doesnotcontain'
THEN 'ISNULL(' + @Field + ','''')' + ' NOT LIKE ' + 'N'''+'%'+@Value + '%' + ''''
END
WHEN @DataType = 'Numeric'
THEN CASE
WHEN @Operator = 'gte'
THEN @Field + ' >= ' + @Value
WHEN @Operator = 'lte'
THEN @Field + ' <= ' + @Value
WHEN @Operator = 'gt'
THEN @Field + ' > ' + @Value
WHEN @Operator = 'lt'
THEN @Field + ' < ' + @Value
WHEN @Operator = 'eq'
THEN @Field + '=' + @Value
WHEN @Operator = 'neq'
THEN @Field + '<>' + @Value
END
WHEN @DataType IN ('DateTime')
THEN CASE
WHEN @Operator = 'gte'
THEN @Field + ' >= ' +''''+ @Value +''''
WHEN @Operator = 'lte'
THEN @Field + ' <= ' +''''+ @Value +''''
WHEN @Operator = 'gt'
THEN @Field + ' > ' +''''+ @Value +''''
WHEN @Operator = 'lt'
THEN @Field + ' < ' +''''+ @Value +''''
WHEN @Operator = 'eq'
THEN @Field + '=' +''''+ @Value +''''
WHEN @Operator = 'neq'
THEN @Field + '<>' +''''+ @Value +''''
END
WHEN @DataType IN ('Date')
THEN CASE
WHEN @Operator = 'gte'
THEN 'CONVERT(varchar(10),'+@Field+',120)' + ' >= ' +''''+ CONVERT(varchar(10),@Value,120) +''''
WHEN @Operator = 'lte'
THEN 'CONVERT(varchar(10),'+@Field+',120)' + ' <= ' +''''+ CONVERT(varchar(10),@Value,120) +''''
WHEN @Operator = 'gt'
THEN 'CONVERT(varchar(10),'+@Field+',120)' + ' > ' +''''+ CONVERT(varchar(10),@Value,120) +''''
WHEN @Operator = 'lt'
THEN 'CONVERT(varchar(10),'+@Field+',120)' + ' > ' +''''+ CONVERT(varchar(10),@Value,120) +''''
WHEN @Operator = 'eq'
THEN 'CONVERT(varchar(10),'+@Field+',120)' + ' = ' +''''+ CONVERT(varchar(10),@Value,120) +''''
WHEN @Operator = 'neq'
THEN 'CONVERT(varchar(10),'+@Field+',120)' + ' <> ' +''''+ CONVERT(varchar(10),@Value,120) +''''
END
WHEN @DataType = 'Boolean'
THEN CASE
WHEN @Operator = 'eq'
THEN @Field + '=' +''''+ @Value +''''
END
END
SET @WhereQuery=
CASE
WHEN @logic = '' THEN '('+@SQLOperator+')'
WHEN @logic in('and','or') AND @RowNum=2 THEN ' '+@logic+ ' '+@SQLOperator+')'
WHEN @logic in('and','or') AND @RowNum=1 THEN '('+@SQLOperator
END
RETURN @WhereQuery
END

What I have tried:

Trying to understand the logic of the function and output as well.

Posted 13-Jul-16 21:13pm

Sambit_Sahoo

Updated 13-Jul-16 21:40pm

Add a Solution

Comments

Suvendu Shekhar Giri 14-Jul-16 3:24am

Haven't you created this?
Best to ask who created it. We can help only if you have a problem/doubt in specific part of the stored proc.

1 solution

Add a Solution

Add your solution here

Treat my content as plain text, not as HTML

Preview 0

…

Existing Members

Sign in to your account

...or Join us

Download, Vote, Comment, Publish.

Your Email
Password
Forgot your password?

Your Email
This email is in use. Do you need your password?
Optional Password

I have read and agree to the Terms of Service and Privacy Policy
Please subscribe me to the CodeProject newsletters

When answering a question please:

Read the question carefully.
Understand that English isn't everyone's first language so be lenient of bad spelling and grammar.
If a question is poorly phrased then either ask for clarification, ignore it, or edit the question and fix the problem. Insults are not welcome.
Don't tell someone to read the manual. Chances are they have and don't get it. Provide an answer or move on to the next question.

Let's work to help developers, not make them feel stupid.

This content, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

OriginalGriff · Answer 1 · 2016-07-13T21:40:00

It's pretty simple - and rather pointless, really.
You pass it text based parameters and it converts them to valid SQL WHERE condition as a string.
So you use it:

SQL

[dbo].[udf_GenerateWhereQuery]('AND', 'nameOfColumn', 'gte', '666', 'numeric')

And it returns

SQL

'AND nameOfColumn >= 666'

Which would I rather read in my code? Not the function call...
The only advantage of this is that it can take values from a DB and generate SQL that can be executed - but that's dangerous as it leaves you open to SQL Injection.