文件:ThinkPHP/Library/Think/Db/Driver/Pgsql.class.php:L41
'SELECT
fields_name AS "field",
fields_type AS "type",
fields_not_null AS "null",
fields_key_name AS "key",
fields_default AS "default",
fields_default AS "extra"
FROM
table_msg ('.$tableName.');'
直接这样将变量$tableName带入会报错: 将函数的参数看成了字段, 报字段不存在的错误

解决办法: 加上单引号
'SELECT
fields_name AS "field",
fields_type AS "type",
fields_not_null AS "null",
fields_key_name AS "key",
fields_default AS "default",
fields_default AS "extra"
FROM
table_msg (\''.$tableName.'\');'