- SET the SESSION group_concat_max_len=102400;

SELECT
BB. Road_name,
BB. Direct_type,
Concat (
'MULTILINESTRING ('
Array_to_string (
ARRAY (
SELECT
The UNNEST (
The ARRAY_AGG (substr (BB. WKT, 11))
)
The ORDER BY
1
),
', '
),
')
) poly real
The FROM
(
SELECT
Rd. Road_name,
Rd. Direct_type,
Rl. WKT -- -- "direction_num section_num", ""," link_num
"The FROM
D_road_direction rd,
D_road_link rl
WHERE
Rd. Road_name=rl. Road_name
The ORDER BY
Rd. Road_name,
Rl direction_num,
Rl section_num,
Rl. Link_num
BB)
GROUP BY
Road_name,
Direct_type
The ORDER BY
Road_name,
direct_type

CodePudding user response:

Be truncated to how long? I haven't left the system table was used to simulate, the look is normal

 SELECT 
COUNT (*), 
LENGTH (concat (
'MULTILINESTRING (' 
Array_to_string (
ARRAY (
SELECT 
The UNNEST (
The ARRAY_AGG (substr (BB) name, 11)) 
) 
The ORDER BY 1 
), 
', '
), 
') 
Poly real)) 
The FROM (
A, SELECT a.n ame FROM pg_settings pg_settings B, pg_settings c 
) bb 

The results
The count poly real
19465109, 178514603,