SELECT
	zmj.*,
	UNNEST ( string_to_array( zmj.字段, ',' ) ) AS tag 
FROM
	表名 zmj,
	generate_series ( 1, ( LENGTH ( zmj.字段 ) - LENGTH ( REPLACE ( zmj.字段, ',', '' ) ) + 1 ) ) AS seq;
 

PostgreSql 字段按逗号分隔成多条数据_分隔