If you’re getting an error that reads “ERROR 1250 (42000): Table ‘…’ from one of the SELECTs cannot be used in global ORDER clause” when using the UNION clause in a MySQL query, it’s probably because you’re qualifying a column name with its table name.
This doesn’t work in MySQL.
To fix this issue, either remove the table name or use a column alias.
Continue readingIf you’re getting error “1054 (42S22): Unknown column ‘…’ in ‘order clause'” when using the UNION clause in MySQL, it could be because you’re trying to reference an aliased column by its column name.
One of the more common error message in MySQL goes like this: “ERROR 1136 (21S01): Column count doesn’t match value count at row 1“.
This error typically occurs when you’re trying to insert data into a table, but the number of columns that you’re trying to insert don’t match the number of columns in the table.
In other words, you’re either trying to insert too many columns, or not enough columns.
Continue readingIf you’re getting the error “ORA-01789: query block has incorrect number of result columns” in Oracle Database, then it’s probably because you’re trying to use an operator such as UNION, INTERSECT, or EXCEPT to run a compound query, but the SELECT statements on either side of the operator return a different number of columns.
To fix this, simply ensure that both queries return the same number of columns.
Continue readingIf you’re getting “ERROR 1250 (42000): Table ‘…’ from one of the SELECTs cannot be used in ORDER clause”, it’s probably because you’re qualifying a column name with its table name when using an operator such as UNION, INTERSECT, or EXCEPT in MariaDB.
To fix this, either remove the table name or use a column alias.
Continue readingIf 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 readingIf 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.
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 readingThere 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 readingIf 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.
Continue reading