XQuery syntax to evaluate math formula

• PatrickSimons

  Right there with Babe

  Points: 786

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  February 25, 2015 at 5:29 am

  #298041

  I want to evaluate a math formula inside of a function, so I can't use dynamic SQL.

  I found that the query on an XML-variable with a literal works well.

  DECLARE @sParsedFormula varchar(200);

  DECLARE @xFormula xml;

  SET @xFormula = '';

  SET @sParsedFormula = '1+2';

  SELECT @xFormula.query('3+3') , @xFormula.query('sql:variable("@sParsedFormula")')

  Output (1st value is correctly evaluated, 2nd not):

  "6", "1+2"

  I can't directly pass @sParsedFormula to the query otherwise I get "The argument 1 of the XML data type method "query" must be a string literal".

  What is the correct XQuery-syntax to evaluate the SQL:variable?

  Tx,

  Patrick

  Patrick SIMONS, MCP

• PatrickSimons

  Right there with Babe

  Points: 786

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  February 27, 2015 at 7:35 am

  #1780597

  I got some help here:

  https://social.msdn.microsoft.com/Forums/sqlserver/en-US/b72d0430-44ff-4ded-a3f2-04591ff32bcc/xquery-syntax-to-evaluate-math-formula?forum=transactsql

  Patrick SIMONS, MCP

• Sean Lange

  SSC Guru

  Points: 286602

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  February 27, 2015 at 7:41 am

  #1780607

  Having read the other location you posted looking for help I agree with Erland 10000%. You are concerned about performance but wanting to use a scalar function. Scalar functions are right next to cursors and while loop on the slow end of the performance options.

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