postgres 如何把多行数据，合并一行，返回json字符串

 需要得格式 String json = "{"1984":"1","1985":"1"}";

SELECT
	concat ( '{', A.strjson, '}' ) 
FROM
	(
	SELECT
		string_agg ( concat ( '"', YEAR, '":', '"', zsxx, '"' ), ',' ) strjson 
	FROM
		"pc_pg_his_sczzzs" 
	WHERE
		xzqbm = '530721' 
	) A

 通过 string_agg 函数 合并列得结果

最终结果：

{"1984":"1","1985":"1","1988":"1","1989":"1","1990":"1","1991":"1","1993":"1","1994":"1","1997":"1","1998":"1","2000":"1","2001":"1","2007":"1","2009":"1","2010":"1","2016":"1","2018":"1","2019":"1","1986":"1","1987":"1","1992":"1","1995":"1","1996":"1","1999":"1","2002":"1","2003":"1","2004":"1","2005":"1","2006":"1","2008":"1","2011":"1","2012":"1","2013":"1","2014":"1","2015":"1","2017":"1","2020":"1","1983":"1","1978":"1","1979":"1","1980":"1","1980":"1","1981":"1","1982":"1.1"}