17. A processor-implemented method comprising: converting a SQL expression into an S-expression tabular structure, wherein said S-expression comprises a nested list; generating a function table based on said S-expression tabular structure, wherein said function table comprises a plurality of functions associated with said S expression tabular structure tabulated against at least one of a function name, a derived column and a derived table; generating an argument table based on said S-expression tabular structure, wherein said argument table comprises a plurality of arguments associated with said S-expression tabular structure tabulated against at least one of an argument type, a function identification, a computed from function, a reference to entity or a literal value; and converting at least one function associated with said S-expression tabular structure to a pre-determined language based on a language map of said pre-determined language and said function table and said argument table.
17. A processor-implemented method comprising: converting a SQL expression into an S-expression tabular structure, wherein said S-expression comprises a nested list; generating a function table based on said S-expression tabular structure, wherein said function table comprises a plurality of functions associated with said S expression tabular structure tabulated against at least one of a function name, a derived column and a derived table; generating an argument table based on said S-expression tabular structure, wherein said argument table comprises a plurality of arguments associated with said S-expression tabular structure tabulated against at least one of an argument type, a function identification, a computed from function, a reference to entity or a literal value; and converting at least one function associated with said S-expression tabular structure to a pre-determined language based on a language map of said pre-determined language and said function table and said argument table. 19. The processor-implemented method of claim 17 , wherein said reconstructing comprises: a) selecting a function name of said at least one function from said function table and selecting at least one of an argument type, a reference to entity, a literal value, a computed from function for said at least one function from said argument table; b) augmenting an S-expression string for said at least one function with said argument type comprising at least one of a base column, a derived column, a base table, or a derived table along with said reference to entity; c) augmenting said S-expression string for said at least one function with said argument type comprising a literal value; and d) recursively performing steps a) to d) for said argument type comprising a computed function.