Fix “The ORDER BY in WITHIN GROUP clause of ‘APPROX_PERCENTILE_CONT’ function must have exactly one expression” in SQL Server

Posted on by Ian

If you’re getting SQL Server error 10751 that reads “The ORDER BY in WITHIN GROUP clause of ‘APPROX_PERCENTILE_CONT’ function must have exactly one expression” it’s probably because you’re using too many ORDER BY expressions with the APPROX_PERCENTILE_CONT() function.

The APPROX_PERCENTILE_CONT() function requires the WITHIN GROUP clause, and that clause requires an ORDER BY sub-clause. However, that ORDER BY sub-clause requires exactly one expression – no more, no less. So, you can’t pass multiple expressions, and you can’t pass zero expressions. It must be exactly one expression.

To fix this issue, be sure to have just one ORDER BY expression in the WITHIN GROUP clause when using the APPROX_PERCENTILE_CONT() function.

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Fixing the Error: “The function ‘LAG’ must have an OVER clause with ORDER BY” in SQL Server

Posted on by Ian

If you’re getting error message 4112 that reads “The function ‘LAG’ must have an OVER clause with ORDER BY” in SQL Server, it’s probably because you’re omitting the ORDER BY clause from the OVER clause when using the LAG() function.

The LAG() function requires an OVER clause that contains an ORDER BY clause. This error happens when we include the OVER clause but not the ORDER BY clause.

To fix this error, add an ORDER BY clause to the OVER clause.

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Why GENERATE_SERIES() Only Returns the First Value in the Series in SQL Server

Posted on by Ian

If you’re using the GENERATE_SERIES() function to create a series of numbers, but you’re finding that only the first value in the series is returned, it could be something very obvious.

The obvious reason this could happen is that your step value is too big. In particular, if the step is so big that it covers the whole series, then it stands to reason that there will only be one value in the series.

If this is an issue for you, you might want to check that you’re using an appropriate step value. Using a smaller step value can help to create a series with more values.

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Oracle Adds Support for IF EXISTS and IF NOT EXISTS Syntax Modifiers

Posted on by Ian

Many RDBMSs implement IF EXISTS and IF NOT EXISTS syntax modifiers that can be used with DDL object creation, modification, and deletion, such as CREATE TABLE and DROP TABLE statements, to name just a couple.

These syntax modifiers allow us to run such statements without getting an error in the event that the object already exists (if we’re trying to create it or modify it) or doesn’t exist (if we’re trying to drop it).

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Fix “An insufficient number of arguments were supplied for the procedure or function GENERATE_SERIES” in SQL Server

Posted on by Ian

If you’re getting error 313 with a message that reads “An insufficient number of arguments were supplied for the procedure or function GENERATE_SERIES” in SQL Server, it’s because you’re not passing enough arguments to the GENERATE_SERIES() function.

The GENERATE_SERIES() function/relational operator accepts a minimum of two arguments, and a maximum of three (at least, this is the case at the time of writing). Passing less than two arguments will result in the above error.

To fix this error, be sure to provide at least two arguments when using the GENERATE_SERIES() function.

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Fix Error Msg 9810 “The datepart … is not supported by date function datetrunc for data type” in SQL Server

Posted on by Ian

If you’re getting SQL Server error msg 9810 that tells you that the datepart “is not supported by date function datetrunc for data type“, it’s probably because you’re using an invalid datepart argument when using the DATETRUNC() function.

For example, this error can occur when using a time date part on a date value (i.e. one that doesn’t have a time component). Conversely, it can also occur when using a date date part on a time value (i.e. one that doesn’t have a date component).

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DROP TABLE IF EXISTS in SQL

Posted on by Ian

In SQL, we can use the DROP TABLE IF EXISTS statement to drop a table only if it exists.

While it may seem obvious that we can only drop a table if it exists (i.e. we can’t drop a table that doesn’t exist), there’s a good reason for using this statement.

The reason we put an IF EXISTS clause into a DROP TABLE statement is to prevent any errors that would occur if the table doesn’t exist.

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Create a Decrementing Series in SQL Server

Posted on by Ian

SQL Server 2022 introduced the GENERATE_SERIES() function that allows us to create a series of values that increment between a given start and end point.

We can create a decrementing series simply by having a greater start point than the end point, while omitting the third argument.

We can also create a decrementing series by using a negative value for the third argument. This obviously requires that the start point is higher than the stop point.

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