In MySQL, SHOW TABLES
is an administrative statement that lists the non-TEMPORARY
tables and views in a given database.
SHOW TABLES
only lists the tables and views for which you have privileges.
In MySQL, SHOW TABLES
is an administrative statement that lists the non-TEMPORARY
tables and views in a given database.
SHOW TABLES
only lists the tables and views for which you have privileges.
In MariaDB, SHOW TABLES
is an administrative statement that lists the non-TEMPORARY
tables, sequences and views in a given database.
The very useful CREATE TABLE IF NOT EXISTS
syntax was finally introduced in Oracle Database – Oracle Database 23c to be precise. This syntax allows us to run a CREATE TABLE
statement without getting an error if the table already exists.
Earlier versions of Oracle don’t support the IF NOT EXISTS
clause, and so if we want to avoid any nasty errors resulting from trying to create a table that already exists, we need to do a bit of extra work.
Dropping a table in SQL easy. You simply use DROP TABLE myTable
where myTable
is the name of the table you want to drop. You can use this method to drop a table in SQL Server via T-SQL script.
But you’ll get an error if the table doesn’t actually exist. That is, unless you check for the existence of the table first.
Below are four ways of using T-SQL to check whether the table exists before dropping it.
Continue readingIn SQLite, you can use the IF NOT EXISTS
clause of the CREATE TABLE
statement to check whether or not a table or view of the same name already exists in the database before creating it.
Creating a table without this clause would normally result in an error if a table of the same name already existed in the database. But when using the IF NOT EXISTS
clause, the statement has no effect if a table already exists with the same name.
T-SQL doesn’t include the IF NOT EXISTS
clause with its CREATE TABLE
statement, like some other DBMSs do.
Therefore, if we want to check for the existence of the table before we create it in SQL Server, we need to use other methods.
Continue readingIn PostgreSQL, we can use the IF EXISTS
clause of the DROP TABLE
statement to check whether the table exists or not before dropping it.
In Oracle Database, there are a number of views that we can query to find out whether a table exists.
Continue readingSome DBMSs such as Oracle, MySQL, and MariaDB have a DESCRIBE
command that returns information about tables and views. It goes DESCRIBE table
where table is the name of the table or view, and it can also be followed by a column name if you only want information about a specific column.
PostgreSQL doesn’t have a DESCRIBE TABLE
command as such, but there are alternatives.
In SQLite, we can use the IF EXISTS
clause of the DROP TABLE
statement to check whether the table exists or not before dropping it.