Eric's another Big Data Blog
If you come from RDBMS, we all know that it is important to have constraints in your database, so that your data integrity will be maintained, like Primary Key, Foreign Key, Unique Indexing etc. However, in Snowflake world, it is very different. Though Snowflake Supports constraints, like the ones I mentioned above, they are NOT […]
Recursive query in SQL can be as useful as recursive functions that developers use all the time. Snowflake has documentations on how to use CTE to construct recursive queries. Example can be found here: Working with CTEs. It uses a simple company employees hierarchy to demonstrate how to run recursive queries, and it also describes […]
We all know that ALTER TABLE is a DDL (Data Definition Language), not a DML (Data Manipulation Language), because ALTER TABLE only changes metadata information about a table, like adding a new column, or changing existing column names.. If you are unsure about the differences between DDL and DML, please refer to this page on […]
By default, GET_DLL function in Snowflake will return TABLE or VIEW without database and schema path. Please see example below: The result is below: You can see that the table name GET_DDL_TEST returned without Database and Schema info. This could be problematic if user is relying on the output to re-create tables or views, and […]
Sometimes it can be confusing when trying to parse JSON string, this is no different when using PARSE_JSON function in Snowflake, especially when there are special characters involved. Look at below examples when I need to have backslash inside the key string: We can see that both of 2 and 3 backslashes produced errors, while […]
Sometimes user can face “JWT token is invalid” error when trying to connect to Snowflake via SnowSQL using key based authentication. To capture this error, logging needs to be enabled for SnowSQL via command line. Use below sample command to redirect logs to a file with DEBUG level logging: And check the log file under […]
Currently Snowflake does not support the change of COLLATIONs at COLUMN level once table is defined. This is documented on Snowflake’s official documentation as below: Once a table column is defined, you cannot change the collation for the column. In other words, after a column has been created with a particular collation using a CREATE TABLE statement, […]
Most of time when Snowflake query complains about something “is not recognized”, it normally means that Snowflake is not able to CAST a given value to a target type. In my case of “Timestamp ‘2020-09-28’ is not recognized”, it means Snowflake is not able to convert value “2020-09-28” to Timestamp value. This sounds a bit […]
Currently in Snowflake, it supports using the precision format of FF<N>, where N is a number between 0 to 9, to display precision part of the timestamp value. To demonstrate how it works, please see below examples: By default the output returns only 3 digits, which is up to milliseconds, is because the session level […]
Currently if you use GROUP BY CUBE clause in Snowflake, it has the limitation of supporting only 7 elements, or the equivalent of 128 grouping sets. This is documented in below Snowflake’s official documentation: GROUP BY CUBE Usage NotesSnowflake allows up to 7 elements (equivalent to 128 grouping sets) in each cube. This same limitation […]