I got pasted a source code to extract a particular dataset and I am having a problem understanding one of the bits. Here’s the part of a query: Could you help me translate what does the inside bracket of this LIKE operator mean? Many thanks in advance. Answer COALESCE takes second argument if first one is NULL. So let me
Tag: coalesce
How to force postgres to return 0 even if there are no rows matching query, using coalesce, group by and join
I’ve been trying hopelessly to get the following SQL statement to return the query results and default to 0 if there are no rows matching the query. This is the intended result: vol | year ——…
Apache Calcite throws error when using COALESCE with untyped nulls only
When runnning SELECT COALESCE(NULL, NULL); on Apache Calcite I get an error which tells that ELSE clause or at least one THEN clause must be non-NULL This happens because COALESCE function is transformed to CASE expression and the latter is validated for whether at least one THEN or ELSE operand is not null. If all are NULL, then the error
Best way to check for “empty or null value”
What is best way to check if value is null or empty string in Postgres sql statements? Value can be long expression so it is preferable that it is written only once in check. Currently I’m using: But it looks a bit ugly. stringexpression may be char(n) column or expression containing char(n) columns with trailing spaces. What is best way?