drop table if exists in teradata

Multiple LIKE clauses may be specified, which allows copying the columns from multiple tables.. jklaverstijn. Syntax for Drop a column. Using the CASE expression you can build complex conditions with ease. However, the reverse is not true. SQL DROP Table Syntax If you use the DELETE statement to remove all the rows in a table, the table still exists until it is removed with the DROP TABLE statement. UPPER and LOWER are ANSI compliant. CREATE TABLE: All variations of CREATE TABLE statement are valid. If our job fails at our application phase, we have to release the lock on the mloaded table. Credit for volatile table SP: Thorkil/Teradata Community. So, as a result of DROP, the table structure and data will be lost permanently. The Teradata database checks the WHEN conditions starting from the first one if it matches the selector value. DROP TABLE tablename Key: You can also specify database in which you are working Example: If tbl_emp is going to be dropped in EMPLOYEE database then, DROP TABLE EMPLOYEE.tbl_emp There are different ways to implement conditional logic in SQL. Drops the definition for the specified table from the data dictionary and drops the object from its containing database or user, depending on the keyword specified. You can drop a table so that the table will be no longer in your database/workspace. How could I possibly use OUTER joins without creating scalability problems? Depending on the actual query i i usually try to rewrite to OLAP functions or Derived Tables with Outer Joins: Thanks Dieter,  I have another question so I will post in a new thread. Mark as New; Bookmark; Subscribe; Mute; RSS Feed; Permalink; Print; Email to a Friend; Report Inappropriate Content; Re: Check if a table exist in PROC SQL Posted 09-13-2016 08:44 AM (26012 views) | In reply to mbsuther . Â, Welcome to the Teradata Forums. "It is a capital mistake to theorize before one has data." The value that corresponds to the first match is returned. If no WHEN matches the selector, than the result specified by the ELSE clause expression is returned. You are trying to run a DML / DDL operation on a table that exists on a different database. I can't be the first non-Teradata user to ask this question. When we drop a column, Teradata Database delete that column in every row in the given table. The following conditions apply to dropping columns from a table. But it's definitely not the best way to get that info, and i doubt that it's best case in any other DBMS. Your email address will not be published. There are many scenarios where it is required to delete data either directly from a table or using another table. You can query catalogs views (ALL_TABLES or USER_TABLE i.e) to check if the required table exists: Relationship Between EXISTS/NOT EXISTS and IN/NOT IN. Teradata - Drop Tables - DROP TABLE command is used to drop a table. EXISTS in Teradata. The following example lists customers and their credit limit according to the credit class assigned to the customer. Syntax UPPER ( expression ) ... Read more » In reality, I am trying to create upwards of 20 different binary indicators, all of which are based on EXISTS (Subquery) in various tables with 1-to-many and many-to-many relationships. Your use of this Teradata website is governed by the. Main Source: Thread on "Delete or Drop a table if it already exists" in the Teradata Community. - …   0 Likes RW9. Teradata: Delete From Table. * , CASE when o.CustomerID is null then 0 else 1 END AS My_Custom_Indicator … SQL DROP Table statement is used to delete or drop a table from a database or SQL Schema. But what the heck can I possibly do to get aroudn this limitation of not being able to use scalar subqueries in my select clause? Rhodochrosite. Your email address will not be published. This question was answered, 4 months ago. We can use ALTER TABLE command to drop a column from an existing table. So while issuing this statement you should be very careful as all the information available to the table will be lost forever. Thanks in advance. There are times when you might want to drop a load of tables from a database at once, rather than deleting them one at a time. CREATE SCHEMA [ IF NOT EXISTS ] schema_name [ WITH ( property_name = expression [, ...] ) ] I understand how to rewrite this using OUTER joins, ... however I am not sure how this works when things get more complicated. Oracle does not provide IF EXISTS clause in the DROP TABLE statement, but you can use a PL/SQL block to implement this functionality and prevent from errors then the table does not exist. Using partitions, we can query the portion of the data. Depending on the actual query i i usually try to rewrite to OLAP functions or Derived Tables with Outer Joins: SELECT a. When the DROP TABLE is issued, data in the table is deleted and the table is dropped. The DROP TABLE statement removes a table definition and all the table's data, metadata, and indexes. Procedure to Change Column Data Types To make a change to a column data type that affects existing column data, use the following procedure. Tags: csv to teradata how to run tpt script in unix Teradata Parallel Transporter Teradata TPT teradata tpt example teradata tpt script tpt in teradata tpt load tpt load in teradata tpt operators in teradata tpt script tpt script example tpt script to load from file to table tpt teradata tpt teradata example tpt utility in teradata what is tpt in teradata For an example, see In searched CASE statement you supply number of conditions (like nested IF … THEN … ELSE statements in other languages) and corresponding values to be assigned to the result if the expression evaluates to true. Mark as New; Bookmark; Subscribe; Mute; RSS Feed; Permalink; Print; Email to a Friend; Report Inappropriate Content; Re: Sas drop teradata table issues Posted 12-28-2018 07:00 AM (1685 views) | In reply to Amicheals . The following example lists customers and assigns to them customer type based on the total amount of purchases they have made. The optional IF EXISTS clause causes the error to be suppressed if the view does not exist. Than you specify a number of values that the selector value should be matched against using the WHEN clause. In general, EXISTS can be used to replace comparisons with IN and NOT EXISTS can be used to replace comparisons with NOT IN. If you use the DELETE statement to remove all the rows in a table, the table still exists until it is removed with the DROP TABLE statement. This is one of my biggest headaches with Teradata, and if I figure this out, maybe I will stop transferring data off Teradata into a competing environment all the time. But I found the DBC.Databases view to allow for a more general answer, even if your database has no tables: sql SELECT 1 FROM DBC.Databases WHERE DatabaseName = 'YOUR_DB' – rodeo90 Nov 5 '20 at 19:11 So check for DataLoad, if exists drop otherwise move to next step. This is only a simple example. SQL provides the much more powerful CASE expression. 0 Likes Reply. RELEASE MLOAD databasename.tablename IN APPLY RELEASE MLOAD -- This statement obtains the Exclusive lock over target tables and frees the target table from any kind of locks. Some of my table sizes approach 1 billion in row count. Attention : il faut utiliser cette commande avec […] La commande DROP TABLE en SQL permet de supprimer définitivement une table d’une base de données. Credit for normal table code: Dieter (dnoeth)/Teradata Community. Required fields are marked *. Sorry to throw a wrench into it. I'm looking for the absolute most efficient syntax to use with this sort of problem - but instead of the example above, assume I am using CASE WHEN EXISTS (Subquery) 20 differnet times on 10 different large tables with one to many relationships. I hope we do not have such syntax in teradata SQL.Anyways, teradata automatically errs if the table being dropped does not exists.for your satisfaction ,using bteq, you can query dbc.tvm table to check the existence of the table.use IF..Then conditional looping as below to drop the table ,if it exists SELECT.....FROM DBC.TVM;If ACTIVITYCOUNT >0 THENDROP TABLE .....; Tags for Drop All Statistics in Teradata. Here is how this applies to our customer type example: The CASE statement must contain at least one expression. If the records are present, then EXISTS will be evaluated true otherwise we can say that the EXISTS condition is considered "to be met" if the sub query returns at least one row. I encountered this problem myself, and the DBC.TablesV view can work if the database has tables already. UPPER & LOWER Function The UPPER and LOWER functions covert the character column values all in uppercase and lowercase respectively. The ELSE part is optional. ELSE: If the total_purchase is bigger or equal to 1000 but less than 100000 than ‘Small’ is returned. An added benefit of this technique (NOT EXISTS) is that the presence of a NULL does not affect the performance. Diamond. Drops an existing table. The DROP TABLE statement removes a table definition and all the table's data, metadata, and indexes. The Teradata database checks the WHEN conditions starting from the first one if it matches the selector value. The optional IF EXISTS clause causes the error to be suppressed if the table does not exist. If the total_purchase is less than 1000, ‘Small’ is returned. Description. You must use an older version of Teradata, this syntax should be supported since 13.10. The following example uses a search condition in a HAVING clause to select from the Employee table those departments with the number 100, 300, 500, or 600, and with a salary average of at least $35,000 but not more than $55,000: SELECT AVG(Salary) FROM Employee WHERE DeptNo IN (100,300,500,600) GROUP BY DeptNo Sample Table and Data Creating Tables: Creating 2 tables with similar structure to understand the logic in details. Table 1 CREATE MULTISET VOLATILE TABLE deletetable( id INTEGER, name VARCHAR(100) ) PRIMARY INDEX(id) ON COMMIT PRESERVE ROWS; Table … Cela supprime en même temps les éventuels index, trigger, contraintes et permissions associées à cette table. However, it was done to shorten the names to ease the equality coding in the subquery. DROP Table statement removes all the data, indexes, triggers, constraints along with the definition of the table. 2 Populate the new table using an INSERT … SELECT request. It will not delete the table if it does not exist. But it's definitely not the best way to get that info, and i doubt that it's best case in any other DBMS.   EXISTS predicate tests the existence of specified rows of a subquery. If INCLUDING PROPERTIES is specified, all of the table properties are copied to the new table. CREATE VOLATILE TABLE: If you include a CREATE VOLATILE TABLE statement in a stored procedure, the volatile table is created in your login database. Hello, I'm working on a code that will help determine if a table exists in a database or not. Query Catalog Views. If you execute operations on Teradata without specifying the database, all operations are execute on the default database for the user. Drop a column in a table in Teradata. DROP VIEW [ IF EXISTS ] view_name Description. Let's say I want to pull a list of my customers and create some sort of binary indicator based on whether they ordered a certain type of product:     You must use an older version of Teradata, this syntax should be supported since 13.10. This statement is used to drop the table if it exists. REPLACE PROCEDURE IF_EXISTS_RENAME(IN table_name VARCHAR(30),IN new_table_name VARCHAR(30))BEGINIF EXISTS(SELECT 1 FROM dbc.tables WHERE 1=1 AND tablename = table_name and databasename=DATABASE) THEN CALL DBC.SysExecSQL('RENAME TABLE ' || table_name ||' to '|| new_table_name);END IF;END; Share. This SQL finds all the tables that match the criteria, in this case the name of the user, and creates the commands that you'd need to use to DROP them. This code won't work when it is run for the first time: DROP TABLE SomeVolatileTable; CREATE VOLATILE TABLE SomeVolatileTable AS ( SELECT TOP 10 * FROM SomeSourceTable ) WITH DATA ON COMMIT PRESERVE ROWS; In sql server you can check if a temporary table exists: IF OBJECT_ID ('tempdb..#SomeTempTable') IS NOT NULL DROP TABLE #SomeTempTable. drop all stats on a table teradata; how to drop stats in teradata; teradata drop all stats; teradata drop statistics on table Drop an existing view. I would to verify if the table exists at the start of a new quarter and, if not, to create it. In addition, we can use the Alter table add partition command to add the new partitions for a table. 1 Create a new table with a different name that contains the changed data type attributes. Since the Customer and Order tables are used in the above Correlated subquery, the table names did not require an alias. If an object with the same name already exists in that database, the result is a runtime exception. In simple CASE statement you provide selector value – in our case this is the credit_class field. We cannot drop indexed columns from a table without first dropping the index on those columns. The LIKE clause can be used to include all the column definitions from an existing table in the new table. For example, A table is created with date as partition column in Hive. 1 answers to this question. Alter table statement is used to change the table structure or properties of an existing table in Hive. In simple CASE statement you provide selector value – in our case this is the credit_class field. Teradata supports several string functions to manipulate the string. EXISTS checks the existence of records in the target table. This is helpful however it feels like I'm being inefficient as the query grows larger. Read the, SELECT with EXISTS (Subquery) in Teradata, Copyright © 2004-2015 Teradata Corporation. Some problems can be solved only by using EXISTS and/or NOT EXISTS predicate. You can drop a base table or materialized global temporary table, depending on the keyword specified. Here I will show you one. Than you specify a number of values that the selector value should be matched against using the WHEN clause. The standard ANSI SQL and the Teradata SQL doesn’t support IF…THEN…ELSE statement or expression.