Class: FluentQuery::Drivers::Shared::Tokens::SQL::Select

Inherits:
FluentQuery::Drivers::Shared::Tokens::SQLToken show all
Defined in:
lib/fluent-query/drivers/shared/tokens/sql/select.rb

Overview

Generic SQL query SELECT token.

Constant Summary

Constants inherited from FluentQuery::Drivers::Shared::Tokens::SQLToken

FluentQuery::Drivers::Shared::Tokens::SQLToken::TRANSFORMER

Instance Method Summary collapse

Methods inherited from FluentQuery::Drivers::Shared::Tokens::SQLToken

#initialize

Constructor Details

This class inherits a constructor from FluentQuery::Drivers::Shared::Tokens::SQLToken

Instance Method Details

#render!(mode = :build) ⇒ Object 



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# File 'lib/fluent-query/drivers/shared/tokens/sql/select.rb', line 22

def render!(mode = :build)
    stack = [ ]
    unknown = [ ]
    fields = [ ]
    aliases = { }
    distinct = false
    
    result = "SELECT "
    processor = @_query.processor
    
    _class = self.unknown_token

    # Process subtokens
    
    @_subtokens.each do |token|
        arguments = token.arguments
        name = token.name

        # Known select process
        if (name == :select) or (name == :distinct)
            length = arguments.length
            
            if length > 0
                first = arguments.first
                
                if first.symbol?
                    stack << arguments
                elsif first.string?
                    stack << processor.process_formatted(arguments, mode)
                else
                    arguments.each do |argument|
                        if argument.array?
                            fields += argument
                        elsif argument.hash?
                            aliases.merge! argument
                        end                        
                    end
                end
            end

            # Closes opened native token with unknown tokens
            if unknown.length > 0
                native = _class::new(@_driver, @_query, unknown)
                stack << native.render!
                unknown = [ ]
            end

        # Unknowns arguments pushes to the general native token
        else
            unknown << token
        end

        distinct = (name == :distinct)
    end

    # Closes opened native token with unknown tokens
    if unknown.length > 0
        native = _class::new(@_driver, @_query, unknown)
        stack << native.render!
        unknown = [ ]
    end

    # process distinct
    if distinct
        result << "DISTINCT "
    end

    # Process stack with results
    
    first = true
                                
    if not fields.empty?
        stack.unshift(fields.uniq)
    end
    
    if not aliases.empty?
        stack.unshift(aliases)
    end

    stack.each do |item|
        
        if item.array?
            if not first
                result << ", "
            end
            
            result << processor.process_identifiers(item) 
            first = false
            
        elsif item.hash?
            fields = [ ]
            
            item.each_pair do |key, value|
                key = @_driver.quote_identifier(key)
                value = @_driver.quote_identifier(value)
                
                fields << (key.to_s + " AS " + value.to_s)
            end

            if not first
                result << ", "
            end
            
            result << fields.join(", ")
            first = false
            
        elsif item.string?
            if not first
                result << ", "
            end
        
            result << item
            first = false
            
        end
    end

    return result
end