If you’re getting an error that reads something like “1052 (23000): Column ‘name’ in field list is ambiguous” in MySQL, it looks like you could be referencing a column name in a query without qualifying it with the table name.
This can happen when you perform a join between tables that use the same name for one or more columns.
To fix this issue, be sure to qualify column names with the table names when performing joins across tables.
Continue readingIf you’re getting an error that reads something like “ERROR 1066 (42000): Not unique table/alias: ‘d’” in MySQL, it could be that you’re trying to assign a duplicate alias to a table. Or it could be that you’re doing a self-join without assigning table aliases.
Table names and aliases must be unique when doing queries in MySQL.
The error can also happen if you use HANDLER to open a table, but then try to open it again before closing it.
To fix this issue, be sure to use unique table aliases in your query. And if you’re using HANDLER, either close the table or continue working with it (without trying to open it again).
If you’re trying to use a common table expression (CTE) that produces XML in SQL Server, but you’re getting error 4121, which reads something like “Cannot find either column “EmployeeData” or the user-defined function or aggregate “EmployeeData.query”, or the name is ambiguous” it might be that you’re trying to query the XML in the outer query, but your CTE isn’t outputting the XML as an actual xml type.
The FOR XML result must be an xml type in order to process the result on the server.
To fix this issue, make sure the CTE outputs the result using the xml data type.
Continue readingIf you’re getting MySQL error 1109 which reads something like “1109 (42S02): Unknown table ‘products’ in HANDLER” in MySQL, it appears that you’re trying to reference a table that’s not currently open when using MySQL’s HANDLER statement.
This can happen when you try to read from a table that you haven’t yet opened. It can also happen when you’ve assigned an alias to the table but you try to reference it without the alias. And it can happen if you try to close a table that isn’t actually open.
Continue readingA common table expression (CTE) in SQL Server is used to create a temporary result set that can be referenced within a SELECT, INSERT, UPDATE, or DELETE statement. A CTE can simplify complex queries and improve readability. However, there are specific rules for using the ORDER BY clause inside a CTE.
Error 156 in SQL Server is a generic error that doesn’t tell us much, other than the fact that we’re using the wrong syntax.
But if you’re running a subquery, and you’re getting error 156, which reads “Incorrect syntax near the keyword ‘WHERE’.” or whatever keyword it’s near, it could be that you haven’t declared an alias for the subquery.
Continue readingIf you’re running a subquery in SQL Server, but you’re getting error 102 that reads something like “Incorrect syntax near ‘;’“, there could be any number of reasons, because this is a generic error that simply means wrong syntax.
But one possible cause could be that you haven’t declared an alias for the subquery.
Continue readingIf you’re getting an error when specifying LAST or PREV for MySQL’s HANDLER statement, it could be that you’re trying to do a table scan using the index syntax.
While the HANDLER statement does accept the LAST and PREV options, we can only use them with an index.
So to fix this issue, be sure to specify an index when using the LAST and PREV options.
If you’re getting MySQL error 1064 which reads something like “1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near ‘READ FIRST’ at line 1” when using the HANDLER statement in MySQL, it could be that you’re qualifying the table with the database name when trying to read from or close a table.
If you’re getting an error that reads “Ambiguous column name“, followed by a column name, in SQL Server, it could be that you’re performing a join on two tables, but you’re not using the table names or aliases when referring to columns within those tables.
To fix this issue, be sure to qualify the columns with their table names or aliases.
Continue reading