Here are a couple of options for getting a list of tables in a database in PostgreSQL.
The first option is a psql command, the second involves querying an information schema view.
Tag: how to
Subtract Hours from a Time Value in SQLite
In SQLite, we can use the TIME() function to subtract one or more hours from a time value.
For datetime values, we can use the DATETIME() function.
3 Ways to Get the Start of the Month in MariaDB
Here are three options for returning the first day of a month in MariaDB.
This could be the first day of the current month, or the first day of the month based on a date that we specify.
Continue readingReturn Only Numeric Values in SQL
If you ever need to use SQL to return just the numeric values in a character column, the method you use will largely depend on your DBMS. Most DBMSs support regular expressions (regex), but some don’t. And some include functions that can detect numeric values.
Here are examples of how to do it in the more popular DBMSs.
Continue reading3 Ways to Get the Definition of a Generated Column in SQLite
When we have a table with a generated column, here are two methods we can use to return its definition.
Continue readingHow to Create a Generated Column in Oracle
Oracle Database supports the creation of generated columns. A generated column is a column whose value is derived from an expression that computes values from other columns.
In Oracle Database, generated columns are usually referred to as virtual columns. Generated columns can also be referred to as computed columns in other RDBMSs (such as SQL Server). Either way, they do pretty much the same thing – they contain an expression that computes a value based on values in other columns in the same table.
Continue readingFind Rows that Contain Uppercase Characters in SQL
Most RDBMSs provide at least a few ways to return rows that contain uppercase characters. Here are some options available in the major RDBMSs.
Continue readingHow to Get the First Day of the Month in Oracle
Here’s an example of returning the first day of a given month in Oracle Database. We can return the first day of the current month, a previous or later month, or the first day of a month based on a specified date.
Continue reading2 Ways to Check your Redis Client Version
Here are two quick and easy options to find out what version of the Redis client (redis-cli) you’re using.
4 Ways to Check your Redis Version
Here are four quick and easy ways to find out what version of Redis you’re using.
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