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Oracle: If Table Exists
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The best and most efficient way is to catch the "table not found" exception: this avoids the overhead of checking if the table exists twice; and doesn't suffer from the problem that if the DROP fails for some other reason (that might be important) the exception is still rai...
sql query to return differences between two tables
I am trying to compare two tables, SQL Server, to verify some data. I want to return all the rows from both tables where data is either in one or the other. In essence, I want to show all the discrepancies. I need to check three pieces of data in doing so, FirstName, LastName and Product.
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How can I list all foreign keys referencing a given table in SQL Server?
I need to remove a highly referenced table in a SQL Server database. How can I get a list of all the foreign key constraints I will need to remove in order to drop the table?
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Check if a temporary table exists and delete if it exists before creating a temporary table
I am using the following code to check if the temporary table exists and drop the table if it exists before creating again. It works fine as long as I don't change the columns. If I add a column later, it will give an error saying "invalid column". Please let me know what I am doing wrong.
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How can I create a copy of an Oracle table without copying the data?
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Just use a where clause that won't select any rows:
create table xyz_new as select * from xyz where 1=0;
Limitations
The following things will not be copied to the new table:
sequences
triggers
indexes
some constraints may not be copied
materialized view logs
This also does no...
Tables instead of DIVs [duplicate]
Under what conditions should you choose tables instead of DIVs in HTML coding?
24 Answers
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How to rename a table in SQL Server?
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To rename a table in SQL Server, use the sp_rename command:
exec sp_rename 'schema.old_table_name', 'new_table_name'
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How to do 3 table JOIN in UPDATE query?
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the answer is yes you can
try it like that
UPDATE TABLE_A a
JOIN TABLE_B b ON a.join_col = b.join_col AND a.column_a = b.column_b
JOIN TABLE_C c ON [condition]
SET a.column_c = a.column_c + 1
EDIT:
For general Update join :
UPDATE TABLEA a
JOIN TABLEB b ...
MySQL InnoDB not releasing disk space after deleting data rows from table
I have one MySQL table using the InnoDB storage engine; it contains about 2M data rows. When I deleted data rows from the table, it did not release allocated disk space. Nor did the size of the ibdata1 file reduce after running the optimize table command.
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PostgreSQL Autoincrement
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Yes, SERIAL is the equivalent function.
CREATE TABLE foo (
id SERIAL,
bar varchar);
INSERT INTO foo (bar) values ('blah');
INSERT INTO foo (bar) values ('blah');
SELECT * FROM foo;
1,blah
2,blah
SERIAL is just a create table time macro around sequences. You can not ...