i use grafana with table panel, i can put 3 column (metric,value,time) but i want put 5 column (metric, metric, value, value, time)
how can i see 5 column in a table?
see below with 3 column
i need 5 column
sql in grafana panel :
that works, i use a new version of table in grafana
You can't have the same name column more than once. Change the name of the columns and it should work.
You can Do that with Grafana tooltip, identical columns name are forbidden by MySQL, nor Grafana. on your query set unique alias for each column.
on your table visualization configuration change the names as you wish.
for example:
SELECT time as time, line as value1, nb_user as value2, os_name as metric1, program as metric2 FROM Toto WHERE $__timeFilter(time) ORDER BY 1
Related
Let's say I have an existing table A with a column called contact_name and a ID column id as the primary key.
All the rows in A have the name value as "NULL" right now.
Another table B has different columns, but one of which is contact_name, and another is ref_id.
Each ref_id in B corresponds to a value of id in A, and there may be multiple rows in B that share the same value for ref_id (meaning they all correspond to a single entry in A).
Let me set up an example:
Table A
id | contact_name
1 | [NULL]
2 | [NULL]
Table B
ref_id | contact_name
1 | "John"
2 | "Helen"
2 | "Alex"
Note there are theoretically other values in each table but for the sake of brevity I'm just showing the values I'm interested in using.
I want to populate contact_name in table A with the first entry of the corresponding contact_name in B, where B.(first)ref_id = A.id, without adding any rows or editing the rest of the rows in either table. That is, I want A in my example to now be:
id | contact_name
1 | "John"
2 | "Helen"
Again, note how the first contact_name value, "Helen", in B is selected, not any other subsequent one, like "Alex".
The MERGE function is made for this. Give it a try:
MERGE INTO TABLEA a USING (
SELECT b.REF_ID, b.CONTACT_NAME
FROM TABLEB) b
ON (a.ID = b.REF_ID)
WHEN MATCHED THEN
UPDATE SET
a.CONTACT_NAME = b.CONTACT_NAME
WHERE a.CONTACT_NAME IS null;
You could try using Five, a low-code development environment that lets you manage your MySQL database, and build a web application on top of it.
Whenever You can add a new column in a Table, Five will give you a prompt where you can use a query to populate that particular column.
Here are the steps:
Import your existing MySQL database into Five
Add a new column to your database.
Five will prompt you to fill in values for the new column. Five gives you four options:
A. you can leave the new column empty,
B. assigned a Default value,
C. Copy Values to an existing field
D. Write a custom query.
Refer to This Screenshot to get an idea how things look inside Five
Hope this helps!
Disclaimer: I work for Five
Imagine there is a table with 1000 columns.
I want to add a row with values for 20 columns and assume NULLs for the rest.
INSERT VALUES syntax can be used for that:
INSERT INTO `tbl` (
date,
p,
... # 18 more names
)
VALUES(
DATE('2020-02-01'),
'p3',
... # 18 more values
)
The problem with it is that it is hard to tell which value corresponds to which column. And if you need to change/comment out some value then you have to make edits in two places.
INSERT SELECT syntax also can be used:
INSERT INTO `tbl`
SELECT
DATE('2020-02-01') AS date,
'p3' AS p,
... # 18 more value AS column
... # 980 more NULL AS column
Then if I need to comment out some column just one line has to be commented out.
But obviously having to set 980 NULLs is an inconvenience.
What is the way to combine both approaches? To achieve something like:
INSERT INTO `tbl`
SELECT
DATE('2020-02-01') AS date,
'p3' AS p,
... # 18 more value AS column
The query above doesn't work, the error is Inserted row has wrong column count; Has 20, expected 1000.
Your first version is really the only one you should ever be using for SQL inserts. It ensures that every target column is explicitly mentioned, and is unambiguous with regard to where the literals in the VALUES clause should go. You can use the version which does not explicitly mention column names. At first, it might seem that you are saving yourself some code. But realize that there is a column list which will be used, and it is the list of all the table's columns, in whatever their positions from definition are. Your code might work, but appreciate that any addition/removal of a column, or changing of column order, can totally break your insert script. For this reason, most will strongly advocate for the first version.
You can try following solution, it is combination of above 2 process which you have highlighted in case study:-
INSERT INTO `tbl` (date, p, 18 other coll names)
SELECT
DATE('2020-02-01') AS date,
'p3' AS p,
... # 18 more value AS column
Couple of things you should consider here are :-
Other 980 Columns should ne Nullable, that means it should hold NULL values.
All 18 columns in Insert line and Select should be in same order so that data will be inserted in same correct order.
To Avoid any confusion, try to use Alease in Select Query same as Insert Table Column name. It will remove any ambiguity.
Hopefully it will work for you.
In BigQuery, the best way to do what you're describing is to first load to a staging table. I'll assume you can get the values you want to insert into JSON format with keys that correspond to the target column names.
values.json
{"date": "2020-01-01", "p": "p3", "column": "value", ... }
Then generate a schema file for the target table and save it locally
bq show --schema project:dataset.tbl > schema.json
Load the new data to the staging table using the target schema. This gives you "named" null values for each column present in the target schema but missing from your json, bypassing the need to write them out.
bq load --replace --source_format=NEWLINE_DELIMIITED_JSON \
project:dataset.stg_tbl values.json schema.json
Now the insert select statement works every time
insert into `project:dataset.tbl`
select * from `project:dataset.stg_tbl`
Not a pure SQL solution but I managed this by loading my staging table with data then running something like:
from google.cloud import bigquery
client = bigquery.Client()
table1 = client.get_table(f"{project_id}.{dataset_name}.table1")
table1_col_map = {field.name: field for field in table1.schema}
table2 = client.get_table(f"{project_id}.{dataset_name}.table2")
table2_col_map = {field.name: field for field in table2.schema}
combined_schema = {**table2_col_map, **table1_col_map}
table1.schema = list(combined_schema.values())
client.update_table(table1_cols, ["schema"])
Explanation:
This will retrieve the schemas of both, convert their schemas into a dictionary with key as column name and value as the actual field info from the sdk. Then both are combined with dictionary unpacking (the order of unpacking determines which table's columns have precedence when a column is common between them. Finally the combined schema is assigned back to table 1 and used to update the table, adding the missing columns with nulls.
I am running a query on the table "performance" and I want to insert a column with the same value for all the rows without using alter, update etc.
I wrote a case statement and it works but is there a more refined way?
here is a short query:
SELECT id, name, class,
CASE
WHEN id IS NOT NULL THEN 'Actuals'
ELSE 'Forecast'
END AS type
FROM performance
Basically I need all the values to be labeled "Actuals".
There are many other datasets for which I will use different labels and then append all of them
Just to be clear - don't need to update the table performance itself
use common table expression for your case.
It will add new column in your existing data and you may use this for your further process.
For your point it is not adding nor inserting anything in your existing db structure.
with CTE as (
SELECT id, name, class,
CASE WHEN id IS NOT NULL THEN 'Actuals' ELSE 'Forecast' END AS type
FROM table_performance
)
select * from CTE ----- It give you all the columns from [table] and add another column as you needed.
OR
You may create a view for same, if this condition is fixed.
I want to make filtration on a column after selecting a specific value of another column in the same table, I tried to use #... special character followed by the column's name to get the address of this value.
My SQL statement is like the following :
SELECT ATTRIBUTE FROM TABLE WHERE FIELD = '#FIELDNAME';
If I used a specific value instead of #FIELDNAME, it will work properly but it will be static but I need it to be dynamic based on the selected value.
Create another table which will have the list of values that are in the FIELDNAME and give each record a unique id ,then retrieve the value depending on what you have selected by the name of the new table's field preceded by '#...'
I don't know if that what are you looking for, please let me know.
If no triggers are allowed, do you have any date/time column in the table? Is it possible to have that extra column anyway to see the time of a newly inserted row?
You may have to check the lastest row entered, save its field value into a variable. Then do the select based on the variable value.
Based on the vague last row id you could try the following (it's not pretty). But again, if you have date/time that's more accurate.
select attribute from table
where field = (select field from table
where rowid =(select max(rowid) from table))
;
upate
Do you have the priviledge to set up your insert command as below:
insert into table (id, col1, col2,...) values (1,'something', 'something',...)
returning id into variable; -- you may either save field or id depending on your table
Then you may use this variable to select the records you want.
certain fields in our database contain calculated functions e.g.
select lastname + ', ' + firstname as fullname from contact where contact.id =$contact$
when viewing the field the correct data is shown (i assume this is because when you open the record, the calculation is executed). however, the data is not 'stored' to the field, and therefore is null until the record is opened. is it possible to 'store' the result to the field, making it possible to search the data?
many thanks
james
EDIT
it is not possible for me to create computed_columns using our software.
the above field is a text feild where either 1) a user can manual type in the required data or 2) the database can generate the answer for you (but only whilst you are looking at the record). i know that if I run the following:
Select * from contact where contact.id =$contact$ for xml auto
i only get lastname, firstname - so i know that the fullname field does not retain its information.
If you are using computed columns in sql server, the column is already searchable regardless of whether the calculation result is stored or not. However, if you would like to make it so that the calculation is not run each time you read the row, you can change that under row properties in your Modify Table GUI.
Use the PERSISTED key word when you create the column
From BOL:
PERSISTED
Specifies that the SQL Server Database Engine will physically store the computed values in the table, and update the values when any other columns on which the computed column depends are updated. Marking a computed column as PERSISTED lets you create an index on a computed column that is deterministic, but not precise. For more information, see Creating Indexes on Computed Columns. Any computed columns that are used as partitioning columns of a partitioned table must be explicitly marked PERSISTED. computed_column_expression must be deterministic when PERSISTED is specified.
This isn't the way computed columns work in SQL Server, so I suspect this is something your client application is doing. How are you looking at the data when the value is computed correctly? Does it work when you view the data in SSMS?
Take a look at http://msdn.microsoft.com/en-us/library/ms191250(v=SQL.90).aspx to see how to create computed columns properly.
eg.
create table TestTable
(a int,
b int,
c as a + b)
insert into TestTable (a,b)
values (1,2)
select * from TestTable
where c = 3
This query is based on the computed column and it returns the row that's been inserted.
You need to use the PERSISTED option on a column when you use CREATE TABLE e.g.
CREATE TABLE test (col_a INT, col_b INT, col_c AS col_A * col_B PERSISTED)