I have two lines of code in SQL that create two tables on the fly, i need to do something like
IF TABLE EXISTS
DROP IT AND CREATE IT AGAIN
ELSE
CREATE IT
my lines are the following ones
CREATE TABLE ##CLIENTS_KEYWORD(client_id int)
CREATE TABLE ##TEMP_CLIENTS_KEYWORD(client_id int)
how can I apply that concept for these two tables in my procedure?
From SQL Server 2016 you can just use
DROP TABLE IF EXISTS ##CLIENTS_KEYWORD
On previous versions you can use
IF OBJECT_ID('tempdb..##CLIENTS_KEYWORD', 'U') IS NOT NULL
/*Then it exists*/
DROP TABLE ##CLIENTS_KEYWORD
CREATE TABLE ##CLIENTS_KEYWORD
(
client_id INT
)
You could also consider truncating the table instead rather than dropping and recreating.
IF OBJECT_ID('tempdb..##CLIENTS_KEYWORD', 'U') IS NOT NULL
TRUNCATE TABLE ##CLIENTS_KEYWORD
ELSE
CREATE TABLE ##CLIENTS_KEYWORD
(
client_id INT
)
Check for the existence by retrieving its object_id:
if object_id('tempdb..##clients_keyword') is not null
drop table ##clients_keyword
What you asked for is:
IF OBJECT_ID('tempdb..##CLIENTS_KEYWORD') IS NOT NULL
BEGIN
DROP TABLE ##CLIENTS_KEYWORD
CREATE TABLE ##CLIENTS_KEYWORD(client_id int)
END
ELSE
CREATE TABLE ##CLIENTS_KEYWORD(client_id int)
IF OBJECT_ID('tempdb..##TEMP_CLIENTS_KEYWORD') IS NOT NULL
BEGIN
DROP TABLE ##TEMP_CLIENTS_KEYWORD
CREATE TABLE ##TEMP_CLIENTS_KEYWORD(client_id int)
END
ELSE
CREATE TABLE ##TEMP_CLIENTS_KEYWORD(client_id int)
Since you're always going to create the table, regardless of whether the table is deleted or not; a slightly optimised solution is:
IF OBJECT_ID('tempdb..##CLIENTS_KEYWORD') IS NOT NULL
DROP TABLE ##CLIENTS_KEYWORD
CREATE TABLE ##CLIENTS_KEYWORD(client_id int)
IF OBJECT_ID('tempdb..##TEMP_CLIENTS_KEYWORD') IS NOT NULL
DROP TABLE ##TEMP_CLIENTS_KEYWORD
CREATE TABLE ##TEMP_CLIENTS_KEYWORD(client_id int)
Related
I want to create a stored procedure to return all column data from a table except one column that key of where condition. The original table will be change a lot during my project, so I don't want to create table with declaring columns. How can I create the table that columns are copy of another table? I'm using SQL Server.
ALTER PROCEDURE [dbo].[SelectCharacterDataById]
#Id INT
AS
BEGIN
SET NOCOUNT ON;
CREATE TABLE #TempTable
AS
SELECT *
FROM dbo.CharacterData
WHERE CharacterID = #Id
ALTER TABLE #TempTable
DROP COLUMN CharacterID
SELECT *
FROM #TempTable
END
in part of code need to make swap between two temp table when i make drop one table and reuse it i can't
create table #temp (id int)
create table #swap (id int)
drop table #temp
select * into #temp from #swap
drop table #swap
drop table #temp
i receive this error
Msg 2714, Level 16, State 1, Line 6
There is already an object named '#temp' in the database.
Just change out your logic flow a little. If all that matters is that #temp is empty when the INSERT happens, this should do what you need.
create table #temp (id int)
create table #swap (id int)
<Add loop logic here>
truncate table #temp
insert #temp(id)
select id from #swap
<Close out loop logic>
drop table #swap
drop table #temp
I also made the column names explicit. SELECT * is an accident waiting to happen in production code.
If I want to do something relatively complicated - something usually done by a stored procedure. Is it possible to make it automatic using a VIEW?
My specific case:
I want output table = input table A + some rows input table B. In a stored procedure, I can make a copy of table A and then INSERT INTO it, but it's not allowed in a view.
Simplified example:
input table is [test_album], and output table = input table + singer Prince.
--create test data
IF OBJECT_ID('[dbo].[test_album]', 'U') IS NOT NULL
DROP TABLE [dbo].[test_album]
CREATE TABLE [test_album] (
id int not null identity(1, 1) primary key,
singer VARCHAR(50) NULL,
album_title VARCHAR(100) NULL
)
INSERT INTO [test_album] (singer, album_title)
VALUES ('Adale', '19'),
('Michael Jaskson', 'Thriller')
--this can be executed as sql code or in stored proc
SELECT *
INTO [result_table]
FROM [test_album]
INSERT INTO [result_table] ([singer])
VALUES ('Prince')
select *
from [result_table]
--id singer album_title
--1 Adale 19
--2 Michael Jaskson Thriller
--3 Prince NULL
----as expected
But I can do this INSERT INTO inside a view.
Real-life case:
additional singers are in a table [extra_singers]
[test_album] may have many other columns (or schema may change) so it's ideal not to type all column names in the code.
--create test data
IF OBJECT_ID('[dbo].[test_album]', 'U') IS NOT NULL
DROP TABLE [dbo].[test_album]
IF OBJECT_ID('[dbo].[extra_singers]', 'U') IS NOT NULL
DROP TABLE [dbo].[extra_singers]
IF OBJECT_ID('[dbo].[result_table]', 'U') IS NOT NULL
DROP TABLE [dbo].[result_table]
CREATE TABLE [test_album] (
id int not null identity(1, 1) primary key,
singer VARCHAR(50) NULL,
album_title VARCHAR(100) NULL,
many_other_columns VARCHAR(100) NULL
)
INSERT INTO [test_album] (singer, album_title)
VALUES ('Adale', '19'),
('Michael Jaskson', 'Thriller')
CREATE TABLE [extra_singers] (
[id] int not null identity(1, 1) primary key,
[name] VARCHAR(50) NULL )
INSERT INTO [extra_singers] ([name])
VALUES ('Prince'),
('Taylor Swift')
--append [extra_singers] to [test_album]
--this can be executed as sql code or in stored proc
SELECT *
INTO [result_table]
FROM [test_album]
INSERT INTO [result_table] ([singer])
SELECT [name]
FROM [extra_singers]
Is there an alternative to this (that is automatic)?
any help's appreciated. Thank u-
a partial solution I can think of:
create view test_view as
select *
from [test_album]
union all
select 3 as id,
'Prince' as singer,
NULL as album_title
but you have to know all the column names in [test_album] and you can't let column [id] do auto-increment
So you may be misunderstanding what a view does, or what an insert is. A view is simply a wrapper around a single select query. It contains exactly one select statement, and nothing else. An insert permanently adds a row of data to a persisted table. The example you gave where you just union the row you want seems valid enough. And certainly if it's the same row you want every time, you would not want to be inserting (or even trying to insert) that row into the underlying table each time
This raises a couple questions though.
If you're always going to be unioning the same single row every time, why not jut add that row to the table?
If, lets say, you don't want that row in the underlying table, cool. But if it's always the same static values, why do you need to include it in the view? Can't it just be assumed it's there?
If it can't be assume to always be the same, you certainly don't want to be changing the VIEW body every time you need it to change. So if it is going to change and you don't want to insert it into the base table, maybe make a second table containing the values you want appended to the base table in the view. Then union the base table and the "extra values" table together instead of a single, hard coded row constructor.
I have a table in SQL Server with bundle of records. I want to convert the ID column which is Primary Key to an identity Column without loss of data. I thought of the following two approaches:
Create a new table with identity & drop the existing table.
Create a new column with identity & drop the existing column.
but it's clear that they can not be implemented because keeping records is my first priority.
Is there another way to do this?
This solution violates your point 2, but there is no other way and I think your aim is to keep the old values, because nothing else makes sense...
You could do the following:
make it possible to insert into identity columns in your table:
set identity_insert YourTable ON
add a new ID column to your table with identity and insert the values from your old columns
turn identity insert off
set identity_insert YourTable OFF
delete old ID column
rename new column to old name
make it to the primary key
The only problem could be that you have your ID column already connected as foreign key to other tables. Then you have a problem with deleting the old column...
In this case you have to drop the foreign key constraints on your ID column after step 3, then do step 4 to 6 and then recreate your foreign key constraints.
As you are using SQL Server 2012, another possible alternative could be to create a sequence object that has a starting value of the highest ID +1 already in your table, then create a default constraint for your column using GET NEXT VALUE FOR and reference your sequence object you just created.
If you have direct access to the Server Database, just go into the design of the table, select the PK column, and change the identity to "Yes". Make sure you set your seed to the max value of that column. The increment is 1 by default. Save the table design and you should be good to go.
Considering the source table isn't too big:
Create new table (with IDENTITY)
Populate new table from existing table (with IDENTITY_INSERT ON)
Drop old table (drop any existing FKs first)
Rename new table to old name (re-establish FKs if needed)
-- Create Sample Existing Table
DROP TABLE IF EXISTS #tblTest
CREATE TABLE #tblTest
(
ID INT NOT NULL
, Val VARCHAR(10) NOT NULL
)
INSERT INTO #tblTest
(
ID
, Val
)
VALUES
(1, 'a')
, (2, 'b')
, (4, 'c')
GO
-- Create and Populate New Table (with IDENTITY_INSERT ON)
DROP TABLE IF EXISTS #tblTestNew
CREATE TABLE #tblTestNew
(
ID INT IDENTITY(1, 1) NOT NULL
, Val VARCHAR(10) NOT NULL
)
SET IDENTITY_INSERT #tblTestNew ON
INSERT INTO #tblTestNew
(
ID
, Val
)
(
SELECT
#tblTest.ID
, #tblTest.Val
FROM
#tblTest
)
SET IDENTITY_INSERT #tblTestNew OFF
GO
-- Rename Existing Table to Old (can use sp_rename instead, but I can't for temp tables)
SELECT * INTO #tblTestOld FROM #tblTest
DROP TABLE #tblTest
GO
-- Rename New Table to Existing (can use sp_rename instead, but I can't for temp tables)
SELECT * INTO #tblTest FROM #tblTestNew
DROP TABLE #tblTestNew
GO
-- Test Inserting new record
INSERT INTO #tblTest (Val)
VALUES ('d')
-- Verify Results
SELECT * FROM #tblTest
EXEC tempdb.sys.sp_help #objname = N'#tblTest'
-- Drop 'Old' Table (when ready)
DROP TABLE IF EXISTS #tblTestOld
-- Cleanup
DROP TABLE IF EXISTS #tblTest
DROP TABLE IF EXISTS #tblTestNew
DROP TABLE IF EXISTS #tblTestOld
If the table is very large, consider the log growth, Recovery Model, possible single-user mode, etc.
create table t1 (col1 int, col2 varchar(10))
insert into t1 values (10, 'olddata')
--add identity col
alter table t1 add col3 int identity(1,1)
GO
--rename or remove old column
alter table t1 drop column col1
--rename new col to old col name
exec sp_rename 't1.col3', 'col1', 'column'
GO
--add new test , review table
insert into t1 values ( 'newdata')
select * from t1
How can I create a temporary table without first creating the columns?
CREATE TABLE #Yaks (
YakID int,
YakName char(30) )
select name
from tempdb..sysobjects
where name like '#yak%'
drop table #yaks
It is a pain to have to define the table first.
Create a (temp) table with the same columns as another (no data copied):
select * into #TempTable
from MyTable
where 1=0
Note: Does not create any Foreign keys, indexes etc...