How to use parameter in postgresql

Question

Use in xml this query searchCategory1=" SELECT "$1" FROM "$2" GROUP BY "$1" ORDER BY "$1"" but error message ERROR: relation "$2" does not exist how can i pix this query? JavaScript questions and answers, JavaScript questions pdf, JavaScript question bank, JavaScript questions and answers pdf, mcq on JavaScript pdf, JavaScript questions and solutions, JavaScript mcq Test , Interview JavaScript questions, JavaScript Questions for Interview, JavaScript MCQ (Multiple Choice Questions)

Answer 1

There are three mistakes visible here: You double-quoted $1 and $2, so they are not interpreted as parameters, but as an object name (they are quoted identifiers). You can use parameters only in prepared statements or PL/pgSQL code. Parameters in queries can only be used in a place where a literal could appear, so they cannot be used for column and table names. You'll have to replace the placeholders before you submit the statement to the database.