In SQLite, the EXCEPT operator can be used to create a compound SELECT statement that returns the subset of rows returned by the left SELECT that are not returned by the right SELECT.
Category: DBMS
Database Management Systems
Fix Msg 512 “Subquery returned more than 1 value” in SQL Server
If you get error Msg 512 that reads “Subquery returned more than 1 value…” in SQL Server, it’s because you’re using a subquery that returns more than one value in a scenario where this is not allowed.
Continue readingFind All Non-Numeric Values in a Column in Oracle
If you ever encounter a character column that should be a numeric column, there’s always a possibility that it contains non-numeric data that you don’t know about.
In Oracle Database, you can run a query like the following to return non-numeric data from the column.
Continue readingSQLite UNION Operator
In SQLite, the UNION operator creates a compound SELECT statement that returns the results of the left and right SELECT statements. In other words, it combines the results from two queries into a single result set.
7 Ways to Find Duplicate Rows while Ignoring the Primary Key in MySQL
Here are seven ways to return duplicate rows in MySQL when those rows have a primary key or other unique identifier column.
Continue readingFix “ERROR 1054 (42S22): Unknown column ‘colname’ in ‘order clause'” in MariaDB
If you’re getting error “ERROR 1054 (42S22): Unknown column ‘colname’ in ‘order clause’” in MariaDB, it may be that you’re trying to reference an aliased column by its column name.
This is a common error when running queries that join two or more tables. It can also happen when using operators such as UNION, INTERSECT, and EXCEPT.
MySQL TABLE Statement
In MySQL, the TABLE statement returns rows and columns of the given table.
The TABLE statement is similar to the SELECT statement, and it can be used as a kind of shorthand version of the SELECT statement.
The TABLE statement was introduced in MySQL 8.0.19.
VALUES Statement in MySQL
In MySQL, the VALUES statement returns a set of one or more rows as a table. Basically, it’s a table value constructor in accordance with the SQL standard, which also functions as a standalone SQL statement.
The VALUES statement was introduced in MySQL 8.0.19.
SHOW TABLES in MySQL
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.
2 Ways to Return Rows that Contain Only Alphanumeric Characters in MariaDB
Below are two methods for returning rows that only contain alphanumeric characters in MariaDB.
Alphanumeric characters are alphabetic characters and numeric characters.
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