根据来自多个其他表的数据动态生成 SQL Insert Rows 数据

Question

I am having total of 6 tables say example table1, table3, table3, table4, table5, table6

I am having a peculiar problem, where i need to generate data for table 6 using data from table 1 to 5.

Where subset of data comes from table 1-4 and another subset comes from table 5, now i need to find a way to merge these data from table 1-4 and table 5 to insert data dynamically into table 6.

to give example, from table 1 to 4 i am able to select the data and retrive where in one of the columns of this data has value in integer form like 2,2,3,4 etc kind.

So if i have 4 rows for table 1 to 4, where column1 has values 2, 2, 3, 4 then it implies i have to loop through 2,2,3,4 times each along with data from table 5 and then insert into table 6.

so in this case my table 1-4 has 4 rows with column 1 having 2,2,3,4 values and table 5 has 10 rows in this case my table 6 will have ((2+2+3+4)*10=110) 110 rows to be inserted.

I am facing challenge in generating insert rows data for table 6 dynamically based on values from table 1-4, table 5.

i believe couple of for loops is required, one to loop through table 1-4, and one more to loop through table 5 and generate the 110 insert rows. I am trying to achieve this using python and DB is postgres.

Answer 1

It sounds like a cross join :

with t1_4 as (
      <whatever where is on the first four tables>
     )
select . . .
from t1_4 cross join lateral
     generate_series(1, t1_4.col1, 1) as gs(n) cross join
     t5

You can insert the results into table6 or use create table as depending on what you really need to do.