#018 Concatenate rows in the same column in Azure SQL

This T-SQL code performs a query on the "f.Combustibleis" table. I'll explain each

1. SELECT [ESTADO_SIGLA], STRING_AGG([FLAG], ',') AS FLAG

   :
   • select: Indicates that the next part of the code will specify which columns will be returned in the query.
   • [ESTADO_SIGLA]: Select the "ESTADO_SIGLA" column.
   • STRING_AGG([FLAG], ',') THE FLAG: Uses the STRING_AGG function to concatenate the values in the "FLAG" column grouped by "ESTADO_SIGLA", separated by a comma (','). The result is renamed "FLAG".

2. FROM [f].[ Fuels]

   :
   • FROM: Indicates the table from which the data will be selected.
   • [f]. [Fuels]: This is the name of the table from which the data will be extracted. The prefix "f." suggests that the table is in a schema called "f".
GROUP BY ESTADO_SIGLA:

3. GROUP BY

   • : Groups the results based on the specified column, in this case, "ESTADO_SIGLA". This means that the concatenation will be performed for each distinct group of values in the "ESTADO_SIGLA" column.

Therefore, the code returns a list of state acronyms ("ESTADO_SIGLA") and their flags ("FLAG") concatenated into a single string, separated by a comma. Each line of the output represents a state and its associated flags. This query is useful when you want to get information about the flags associated with each state in a fuel table.