Query a value from one table and use that value as table to query sub values
I have multiple tables in PostgreSQL named a
, b
and data_X_XX
where X
can be any value.data_X_XX
contains these columns: azimuth
, skew
and tilt
.b
contains these columns: a_id
, data_table_name
, serial_no
. data_table_name
will contain the names of tables data_X_XX
.a
contains these columns: id
, name
, location
.
Now, I want to select the values of azimuth
from data_X_XX
and display them as:
a.name, b.serial_no, data_X_XX.azimuth
I have tried select azimuth from b.data_table_name where b.data_table_name='data_X_XX'
, and select azimuth from (select data_table_name from b)
; this all returns an error.
What am I doing wrong? Any help will be highly appreciated.
database postgresql
add a comment |
I have multiple tables in PostgreSQL named a
, b
and data_X_XX
where X
can be any value.data_X_XX
contains these columns: azimuth
, skew
and tilt
.b
contains these columns: a_id
, data_table_name
, serial_no
. data_table_name
will contain the names of tables data_X_XX
.a
contains these columns: id
, name
, location
.
Now, I want to select the values of azimuth
from data_X_XX
and display them as:
a.name, b.serial_no, data_X_XX.azimuth
I have tried select azimuth from b.data_table_name where b.data_table_name='data_X_XX'
, and select azimuth from (select data_table_name from b)
; this all returns an error.
What am I doing wrong? Any help will be highly appreciated.
database postgresql
add a comment |
I have multiple tables in PostgreSQL named a
, b
and data_X_XX
where X
can be any value.data_X_XX
contains these columns: azimuth
, skew
and tilt
.b
contains these columns: a_id
, data_table_name
, serial_no
. data_table_name
will contain the names of tables data_X_XX
.a
contains these columns: id
, name
, location
.
Now, I want to select the values of azimuth
from data_X_XX
and display them as:
a.name, b.serial_no, data_X_XX.azimuth
I have tried select azimuth from b.data_table_name where b.data_table_name='data_X_XX'
, and select azimuth from (select data_table_name from b)
; this all returns an error.
What am I doing wrong? Any help will be highly appreciated.
database postgresql
I have multiple tables in PostgreSQL named a
, b
and data_X_XX
where X
can be any value.data_X_XX
contains these columns: azimuth
, skew
and tilt
.b
contains these columns: a_id
, data_table_name
, serial_no
. data_table_name
will contain the names of tables data_X_XX
.a
contains these columns: id
, name
, location
.
Now, I want to select the values of azimuth
from data_X_XX
and display them as:
a.name, b.serial_no, data_X_XX.azimuth
I have tried select azimuth from b.data_table_name where b.data_table_name='data_X_XX'
, and select azimuth from (select data_table_name from b)
; this all returns an error.
What am I doing wrong? Any help will be highly appreciated.
database postgresql
database postgresql
edited Nov 22 at 22:48
404
3,0601626
3,0601626
asked Nov 22 at 18:28
Hunzla
31
31
add a comment |
add a comment |
1 Answer
1
active
oldest
votes
Because the table names for data_x_xx
are dynamic, you will have to use dynamic sql. And for the sake of being able to return it in a table structure, I'll put it in a function:
CREATE OR REPLACE FUNCTION my_func()
RETURNS TABLE (name TEXT, serial_no ???, azimuth ???) AS
$$
BEGIN
RETURN QUERY EXECUTE
'SELECT a.name, b.serial_no, (SELECT azimuth FROM ' || b.data_table_name || ')
FROM a
JOIN b ON a.id = b.a_id';
END
$$
LANGUAGE plpgsql STABLE;
Replace ???
with the actual data type.
Thank you, that solved my issue. Although, I had to make changes according to the table requirements. cheers!!
– Hunzla
Nov 28 at 9:17
add a comment |
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1 Answer
1
active
oldest
votes
1 Answer
1
active
oldest
votes
active
oldest
votes
active
oldest
votes
Because the table names for data_x_xx
are dynamic, you will have to use dynamic sql. And for the sake of being able to return it in a table structure, I'll put it in a function:
CREATE OR REPLACE FUNCTION my_func()
RETURNS TABLE (name TEXT, serial_no ???, azimuth ???) AS
$$
BEGIN
RETURN QUERY EXECUTE
'SELECT a.name, b.serial_no, (SELECT azimuth FROM ' || b.data_table_name || ')
FROM a
JOIN b ON a.id = b.a_id';
END
$$
LANGUAGE plpgsql STABLE;
Replace ???
with the actual data type.
Thank you, that solved my issue. Although, I had to make changes according to the table requirements. cheers!!
– Hunzla
Nov 28 at 9:17
add a comment |
Because the table names for data_x_xx
are dynamic, you will have to use dynamic sql. And for the sake of being able to return it in a table structure, I'll put it in a function:
CREATE OR REPLACE FUNCTION my_func()
RETURNS TABLE (name TEXT, serial_no ???, azimuth ???) AS
$$
BEGIN
RETURN QUERY EXECUTE
'SELECT a.name, b.serial_no, (SELECT azimuth FROM ' || b.data_table_name || ')
FROM a
JOIN b ON a.id = b.a_id';
END
$$
LANGUAGE plpgsql STABLE;
Replace ???
with the actual data type.
Thank you, that solved my issue. Although, I had to make changes according to the table requirements. cheers!!
– Hunzla
Nov 28 at 9:17
add a comment |
Because the table names for data_x_xx
are dynamic, you will have to use dynamic sql. And for the sake of being able to return it in a table structure, I'll put it in a function:
CREATE OR REPLACE FUNCTION my_func()
RETURNS TABLE (name TEXT, serial_no ???, azimuth ???) AS
$$
BEGIN
RETURN QUERY EXECUTE
'SELECT a.name, b.serial_no, (SELECT azimuth FROM ' || b.data_table_name || ')
FROM a
JOIN b ON a.id = b.a_id';
END
$$
LANGUAGE plpgsql STABLE;
Replace ???
with the actual data type.
Because the table names for data_x_xx
are dynamic, you will have to use dynamic sql. And for the sake of being able to return it in a table structure, I'll put it in a function:
CREATE OR REPLACE FUNCTION my_func()
RETURNS TABLE (name TEXT, serial_no ???, azimuth ???) AS
$$
BEGIN
RETURN QUERY EXECUTE
'SELECT a.name, b.serial_no, (SELECT azimuth FROM ' || b.data_table_name || ')
FROM a
JOIN b ON a.id = b.a_id';
END
$$
LANGUAGE plpgsql STABLE;
Replace ???
with the actual data type.
answered Nov 22 at 23:04
404
3,0601626
3,0601626
Thank you, that solved my issue. Although, I had to make changes according to the table requirements. cheers!!
– Hunzla
Nov 28 at 9:17
add a comment |
Thank you, that solved my issue. Although, I had to make changes according to the table requirements. cheers!!
– Hunzla
Nov 28 at 9:17
Thank you, that solved my issue. Although, I had to make changes according to the table requirements. cheers!!
– Hunzla
Nov 28 at 9:17
Thank you, that solved my issue. Although, I had to make changes according to the table requirements. cheers!!
– Hunzla
Nov 28 at 9:17
add a comment |
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