What is NULLIF() and How to Use it in PostgreSQL? It is a built-in function in Postgres that accepts a couple of arguments and retrieves a NULL value if both arguments are equal or if either of the specified arguments is NULL. It retrieves the first argument if both arguments are not...
Postgres also supports a unique object-relational model, which is generally not found in counterparts likePostgres vs MySQLand MariaDB. This feature allows users to define custom data types if the already rich data types are not enough for the use case. Key Features of PostgreSQL Other than the...
COALESCE is a system in-built function that can be considered one of the conditional expressions available in PostgreSQL. NULLIF, GREATEST, LEAST, and COALESCE are the types of conditional expressions in PostgreSQL. The COALESCE function returns the first non-NULL expression in the specified list. ...
You can update the values of an existing entry by querying for the record you want and setting the column to the value you wish to use. You can query for theswingrecord (this will matcheveryswing in your table) and change its color tored. This could be useful if you gave the swing ...
The subquery written in the PostgreSQL EXISTS operator is inefficient as it executes each row of the outer query’s table. So it is not good practice to use EXISTS as we have other more efficient ways to write SQL queries. If the PostgreSQL subquery returns us the NULL result, then the ...
First, the prompt will ask you to specify a name for the new role. The following example names the rolesammybut you can name yours whatever you like: Output Enter name of role to add:sammy Next, you’ll be asked if the new role should be a superuser. In PostgreSQL, a superuser rol...
Deleting PostgreSQL sequences To delete a PostgreSQL sequence, you can use the same command as that for deleting tables - DROP. Before removing a sequence, make sure that no other tables or functions are using it, since they will be affected if the sequence is removed. ...
The next step is to create a trigger and tell it to call this function: 1 2 3 CREATETRIGGERxtrig BEFOREINSERTONt_temperature FOREACHROWEXECUTEPROCEDUREf_temp(); Our trigger will only fire on INSERT (shortly before it happens). What is also noteworthy here: In PostgreSQL, a trigger on a...
PostgreSQL provides a built-in TO_CHAR() function that converts the given timestamp to a string. It utilizes a format mask to convert the input value to a stri…
We can use an alternate function to create a UUID. Conclusion A universally unique identifier (UUID) serves as an identifier used for generating a unique value within a database. The UUID data type is unique as compared to a serial data type.PostgreSQL UUID, as defined by RFC 4122 standards...