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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Database Management Systems
Fix Error “ORA-01790: expression must have same datatype as corresponding expression”
If you’re getting the error “ORA-01790: expression must have same datatype as corresponding expression” in Oracle Database, it’s probably because you’re using an operator such as UNION, INTERSECT, or EXCEPT to run a compound query, but the columns returned by each query use different data type groups.
To fix this issue, you’ll need to ensure that each column returned by the second query uses the same data type group as the corresponding column in the first query.
Continue reading5 Ways to Select Rows with the Minimum Value for their Group in SQL
Here are five options for using SQL to return only those rows that have the minimum value within their group.
These examples work in most major RDBMSs, including MySQL, MariaDB, Oracle, PostgreSQL, SQLite, and SQL Server.
Continue readingFix Error 1064 (42000) when using the MINUS Operator in MariaDB
There are at least a few possible reasons you might be getting the dreaded error 1064 (42000) that reads “You have an error in your SQL syntax…” etc when trying to use the MINUS operator in MariaDB.
I’ll explore these below and offer some solutions.
Continue readingMySQL UNION Clause
In MySQL, the UNION clause combines the results from multiple queries into a single result set.
3 Ways to Select the Row with the Minimum Value in SQL
Here are three examples of using SQL to find and select the row with the minimum value in a given column.
The examples work in most major RDBMSs, including MySQL, MariaDB, PostgreSQL, SQLite, Oracle, and SQL Server.
Continue readingSHOW TABLES in MariaDB
In MariaDB, SHOW TABLES is an administrative statement that lists the non-TEMPORARY tables, sequences and views in a given database.
Oracle INTERSECT Operator Explained
In Oracle Database, the INTERSECT operator is used to create a compound query that returns the intersection of the results of the left and right SELECT statements. In other words, it combines two queries, but returns only those rows that are returned in both queries.
6 Ways to Select Duplicate Rows in Oracle
The following examples return duplicate rows from an Oracle Database table.
Continue readingFix “ERROR:Â missing FROM-clause entry for table” in PostgreSQL when using UNION, EXCEPT, or INTERSECT
If you’re getting “ERROR: missing FROM-clause entry for table” in PostgreSQL when using an operator such as UNION, INTERSECT, or EXCEPT, it could be because you’re qualifying a column name with its table name.
To fix this, either remove the table name or use a column alias.
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