Method parseJoinCommand

parser/parser.go:570–617

parseJoinCommand - Return ast.JoinCommand created from tokens and validate the syntax Example of input parsable to the ast.JoinCommand: JOIN table on table.one EQUAL table2.one;

()

// Example of input parsable to the ast.JoinCommand:
// JOIN table on table.one EQUAL table2.one;
func (parser *Parser) parseJoinCommand() (ast.Command, error) {
	// parser has either token.JOIN, token.LEFT, token.RIGHT, token.INNER or token.FULL
	var joinCommand *ast.JoinCommand

	if parser.currentToken.Type == token.JOIN {
		joinCommand = &ast.JoinCommand{Token: parser.currentToken}
		joinCommand.JoinType = token.Token{Type: token.INNER, Literal: token.INNER}
	} else {
		joinTypeTokenType := parser.currentToken
		parser.nextToken()
		err := validateToken(parser.currentToken.Type, []token.Type{token.JOIN})
		if err != nil {
			return nil, err
		}
		joinCommand = &ast.JoinCommand{Token: parser.currentToken}
		joinCommand.JoinType = joinTypeTokenType
	}

	// token.JOIN no longer needed
	parser.nextToken()

	err := validateToken(parser.currentToken.Type, []token.Type{token.IDENT})
	if err != nil {
		return nil, err
	}

	joinCommand.Name = ast.Identifier{Token: parser.currentToken}
	parser.nextToken()

	err = validateTokenAndSkip(parser, []token.Type{token.ON})
	if err != nil {
		return nil, err
	}

	var expressionIsValid bool
	expressionIsValid, joinCommand.Expression, err = parser.getExpression()
	if err != nil {
		return nil, err
	}

	if !expressionIsValid {
		return nil, &LogicalExpressionParsingError{}
	}

	parser.skipIfCurrentTokenIsSemicolon()

	return joinCommand, nil
}

// parseUpdateCommand - Return ast.parseUpdateCommand created from tokens and validate the syntax
//