I want a list of properties about a given table and for a specific record of data from that table - in one result
Something like this:
Column Name , DataLength, SchemaLengthMax
...and for only one record (based on a where filter)
So what Im thinking is something like this:
- Get a list of columns from sys.columns and also the schema-based maxlength value
- populate column names into a temp table that includes (column_name, data_length, schema_size_max)
- now loop over that temp table and for each column name, fetch the data for that column based on a specific record, then update the temp table with the length of this data
- finally, select from the temp table
sound reasonable?
Yup. That way works. Not sure if it's the best, since it involves one iteration per column along with the where condition on the source table.
Consider this, instead :
Get the candidate records into a temporary table after applying the where condition. Make sure to get a primary key. If there is no primary key, get a rowid. (assuming SQL Server 2005 or above).
Create a temporary table (Say, #RecValueLens) that has three columns : Primary_key_Value, MyColumnName, MyValueLen
Loop through the list of column names (after taking only the column names into another temporary table) and build sql statement shown in Step 4.
Insert Into #RecValueLens (Primary_Key_Value, MyColumnName, MyValueLen)
Select Max(Primary_Key_Goes_Here), Max('Column_Name_Goes_Here') as ColumnName, Len(Max(Column_Name)) as ValueMyLen From Source_Table_Goes_Here
Group By Primary_Key_Goes_Here
So, if there are 10 columns, you will have 10 insert statements. You could either insert them into a temporary table and run it as a loop. If the number of columns is few, you could concatenate all statements into a single batch.
Run the SQL Statement(s) from above. So, you have Record-wise, column-wise, Value lengths. What is left is to get the column definition.
Get the column definition from sys.columns into a temporary table and join with the #RecValueLens to get the output.
Do you want me to write it for you ?
Related
We are trying to copy data from one table to another using an INSERT INTO ... SELECT statement.
Our original table schema is as follows, with several columns including a repeated record containing 5 structs of various data types:
original table schema
We want an exact copy of this table, plus 3 new regular columns, so made an empty table with the new schema. However when using the following code the input table ends up with fewer rows overall than the original table.
insert into input_table
select column1, column2, null as newcolumn1, null as newcolumn2, null as newcolumn3,
array_agg(struct (arr.struct1, arr.struct2, arr.struct3, arr.struct4, arr.struct5)) as arrayname, column3
from original_table, unnest(arrayname) as arr
group by column1, column2, column3;
We tried the solution from this page: How to copy data from one table into another table which has a record repeated column in GCP Bigquery
but the query would error as it would treat the 5 structs within the array as arrays themselves (data type = eg. string, mode = repeated, rather than nullable/required).
The error we see says that our repeated record column "has type ARRAY<STRUCT<struct1name ARRAY, struct2name ARRAY, struct3name ARRAY, ...>> which cannot be inserted into column summary, which has type ARRAY<STRUCT<struct1name STRING, struct2name STRING, struct3name STRING, ...>> at [4:1]"
Additionally, a query to find rows that exist in the original but not in the input table returns no results.
We also need the columns in this order (cannot do a simple copy of the table and add the 3 new columns at the end).
Why are we losing rows when using the above code to do an insert into... select?
Is there a way to copy over the data in this way and retain the exact number of rows?
As part of my classes on relational databases, I have to create procedures as part of package to fill some of the tables of an Oracle database I created with random data, more specifically the tables community, community_account and community_login_info (see ERD linked below). I succeeded in doing this for tables community and community_account, however I'm having some problems with generating data for table community_login_info. This serves as an intermediary table between the many to many relationship of community and community_account, linking the id's of both tables.
My latest approach was to create an associative array with the structure of the target table community_login_info. I then do a cross join of community and community_account (there's already random data in there) along with random timestamps, bulk collect that result into the variable of the associative array and then insert those contents into the target table community_login_info. But it seems I'm doing something wrong since Oracle returns error ORA-00947 'not enough values'. To me it seems all columns the target table get a value in the insert, what am I missing here? I added the code from my package body below.
ERD snapshot
PROCEDURE mass_add_rij_koppeling_community_login_info
IS
TYPE type_rec_communties_accounts IS RECORD
(type_community_id community.community_id%type,
type_account_id community_account.account_id%type,
type_start_timestamp_login community_account.start_timestamp_login%type,
type_eind_timestamp_login community_account.eind_timestamp_login%type);
TYPE type_tab_communities_accounts
IS TABLE of type_rec_communties_accounts
INDEX BY pls_integer;
t_communities_accounts type_tab_communities_accounts;
BEGIN
SELECT community_id,account_id,to_timestamp(start_datum_account) as start_timestamp_login, to_timestamp(eind_datum_account) as eind_timestamp_login
BULK COLLECT INTO t_communities_accounts
FROM community
CROSS JOIN community_account
FETCH FIRST 50 ROWS ONLY;
FORALL i_index IN t_communities_accounts.first .. t_communities_accounts.last
SAVE EXCEPTIONS
INSERT INTO community_login_info (community_id,account_id,start_timestamp_login,eind_timestamp_login)
values (t_communities_accounts(i_index));
END mass_add_rij_koppeling_community_login_info;
Your error refers to the part:
INSERT INTO community_login_info (community_id,account_id,start_timestamp_login,eind_timestamp_login)
values (t_communities_accounts(i_index));
(By the way, the complete error message gives you the line number where the error is located, it can help to focus the problem)
When you specify the columns to insert, then you need to specify the columns in the VALUES part too:
INSERT INTO community_login_info (community_id,account_id,start_timestamp_login,eind_timestamp_login)
VALUES (t_communities_accounts(i_index).community_id,
t_communities_accounts(i_index).account_id,
t_communities_accounts(i_index).start_timestamp_login,
t_communities_accounts(i_index).eind_timestamp_login);
If the table COMMUNITY_LOGIN_INFO doesn't have any more columns, you could use this syntax:
INSERT INTO community_login_info
VALUE (t_communities_accounts(i_index));
But I don't like performing inserts without specifying the columns because I could end up inserting the start time into the end time and vice versa if I haven't defined the columns in exactly the same order as the table definition, and if the definition of the table changes over time and new columns are added, you have to modify your procedure to add the new column even if the new column goes with a NULL value because you don't fill up that new column with this procedure.
PROCEDURE mass_add_rij_koppeling_community_login_info
IS
TYPE type_rec_communties_accounts IS RECORD
(type_community_id community.community_id%type,
type_account_id community_account.account_id%type,
type_start_timestamp_login community_account.start_timestamp_login%type,
type_eind_timestamp_login community_account.eind_timestamp_login%type);
TYPE type_tab_communities_accounts
IS TABLE of type_rec_communties_accounts
INDEX BY pls_integer;
t_communities_accounts type_tab_communities_accounts;
BEGIN
SELECT community_id,account_id,to_timestamp(start_datum_account) as start_timestamp_login, to_timestamp(eind_datum_account) as eind_timestamp_login
BULK COLLECT INTO t_communities_accounts
FROM community
CROSS JOIN community_account
FETCH FIRST 50 ROWS ONLY;
FORALL i_index IN t_communities_accounts.first .. t_communities_accounts.last
SAVE EXCEPTIONS
INSERT INTO community_login_info (community_id,account_id,start_timestamp_login,eind_timestamp_login)
values (select community_id,account_id,start_timestamp_login,eind_timestamp_login
from table(cast(t_communities_accountsas type_tab_communities_accounts)) a);
END mass_add_rij_koppeling_community_login_info;
I have a table where I have ranked all the rows based on the created date column and have the rank indicated on the table as below
main table
I would like to create a cross-reference table with the golden record as the recurring column and the other two records as associated records as below.
output desired
I would like to know how I can achieve this using SQL.
I have tried creating a seperate table with all ID numbers (Rank = 1) and then joining it with the main table to get the ones with rank 1,2 and 3 associated with it. But it doesnt seem to work as I intend to.
output
I have not tested but something like this should work. You might want to add a name_id field.
select b.id_number,a.id_number
from table a
join table b on a.name=b.name
where b.rank=1
I'm copying the contents of a table into another identical table. But there are already data in the destination table.
Some data in the destination table has the same code as the source table.
Is it possible to skip the duplicates and not to block the insertion for the rest of the data without it failing?
insert into [DB2].[dbo].[MAN] values([MAN],[DES])
SELECT [MAN]
,[DES]
FROM [DB1].[dbo].[MAN]
You can use NOT EXISTS :
INSERT INTO [DB2].[dbo].[MAN] ([MAN], [DES])
SELECT M.[MAN], M.[DES]
FROM [DB1].[dbo].[MAN] AS M
WHERE NOT EXISTS (SELECT 1 FROM [DB2].[dbo].[MAN] M1 WHERE M1.COL = M.COL);
You need to change the M1.COL = M.COL with your actual column name from which you can identify the duplicate values.
If you have your unique col then you can go like this.
insert into [DB2].[dbo].[MAN] values([MAN],[DES])
SELECT [MAN]
,[DES]
FROM [DB1].[dbo].[MAN] WHERE uniqueCol NOT IN (SELECT uniqueCol FROM [DB2].[dbo].[MAN])
Otherwise append few columns to get unique one and compare like that.
I am very new to SQL and SQL server, would appreciate any help with the following problem.
I am trying to update a share price table with new prices.
The table has three columns: share code, date, price.
The share code + date = PK
As you can imagine, if you have thousands of share codes and 10 years' data for each, the table can get very big. So I have created a separate table called a share ID table, and use a share ID instead in the first table (I was reliably informed this would speed up the query, as searching by integer is faster than string).
So, to summarise, I have two tables as follows:
Table 1 = Share_code_ID (int), Date, Price
Table 2 = Share_code_ID (int), Share_name (string)
So let's say I want to update the table/s with today's price for share ZZZ. I need to:
Look for the Share_code_ID corresponding to 'ZZZ' in table 2
If it is found, update table 1 with the new price for that date, using the Share_code_ID I just found
If the Share_code_ID is not found, update both tables
Let's ignore for now how the Share_code_ID is generated for a new code, I'll worry about that later.
I'm trying to use a merge query loosely based on the following structure, but have no idea what I am doing:
MERGE INTO [Table 1]
USING (VALUES (1,23-May-2013,1000)) AS SOURCE (Share_code_ID,Date,Price)
{ SEEMS LIKE THERE SHOULD BE AN INNER JOIN HERE OR SOMETHING }
ON Table 2 = 'ZZZ'
WHEN MATCHED THEN UPDATE SET Table 1.Price = 1000
WHEN NOT MATCHED THEN INSERT { TO BOTH TABLES }
Any help would be appreciated.
http://msdn.microsoft.com/library/bb510625(v=sql.100).aspx
You use Table1 for target table and Table2 for source table
You want to do action, when given ID is not found in Table2 - in the source table
In the documentation, that you had read already, that corresponds to the clause
WHEN NOT MATCHED BY SOURCE ... THEN <merge_matched>
and the latter corresponds to
<merge_matched>::=
{ UPDATE SET <set_clause> | DELETE }
Ergo, you cannot insert into source-table there.
You could use triggers for auto-insertion, when you insert something in Table1, but that will not be able to insert proper Shared_Name - trigger just won't know it.
So you have two options i guess.
1) make T-SQL code block - look for Stored Procedures. I think there also is a construct to execute anonymous code block in MS SQ, like EXECUTE BLOCK command in Firebird SQL Server, but i don't know it for sure.
2) create updatable SQL VIEW, joining Table1 and Table2 to show last most current date, so that when you insert a row in this view the view's on-insert trigger would actually insert rows to both tables. And when you would update the data in the view, the on-update trigger would modify the data.