POSTGRESQL：創建表為選擇列的特定類型

Question

我有一個混合類型的數據（真實，整數，字符...）的表，但我只會恢復具有真實值的列。

我可以構造這個：

SELECT 'SELECT ' || array_to_string(ARRAY(
select 'o' || '.' || c.column_name 
from information_schema.columns as c
where table_name = 'final_datas'
and c.data_type = 'real'), ',') || ' FROM final_datas as o' As sqlstmt

這給出了：

"SELECT o.random,o.struct2d_pred2_num,o.pfam_num,o.transmb_num [...] FROM final_datas as o"

我想用這些列創建一個表。 當然，這樣做是行不通的：

create table table2 as (
SELECT 'SELECT ' || array_to_string(ARRAY(
select 'o' || '.' || c.column_name 
from information_schema.columns as c
where table_name = 'final_datas'
and c.data_type = 'real'), ',') || ' FROM final_datas as o' As sqlstmt
)

建議？

Answer 1

您需要將整個CREATE TABLE語句生成為動態SQL：

SELECT 'CREATE TABLE table2 AS SELECT ' || array_to_string(ARRAY(
select 'o' || '.' || c.column_name 
from information_schema.columns as c
where table_name = 'final_datas'
and c.data_type = 'real'), ',') || ' FROM final_datas as o' As sqlstmt

可以使用EXECUTE sqlstmt;運行結果EXECUTE sqlstmt;