带有间隔列名别名的 PHP 查询字符串

下面是我通过 php 作为字符串发送的 sql 查询的一部分，它成功运行。我需要做的就是将列名（包含"_"）更改为空格。

SELECT DISTINCT(g.test_case_id), test_case_path AS test_case, build_name, g.total_files_covered, g.total_files_in_build, round(cast(g.total_files_covered as numeric)/cast(g.total_files_in_build as numeric),4)*100 as file_coverage, g.total_functions_covered , g.total_functions_in_build, round(cast(g.total_functions_covered as numeric)  / cast(g.total_functions_in_build as numeric) ,4)*100 as function_coverage,run_duration AS run_duration_in_seconds FROM ( .... )

例如，最后一个列名是 run_duration_in_seconds将其更改为 run duration in seconds 。当我在列名别名（带空格）周围使用块引号从我的 php 函数执行查询时。我收到错误：

Warning: pg_query(): Query failed: ERROR:  syntax error at or near "`"
LINE 2: ...ric) ,4)*100 as function_coverage,run_duration AS `run durat...  

我应该如何将列名别名（用空格而不是下划线）添加到查询中，以便它可以由 php pg_query 函数运行？

任何帮助将不胜感激。