Using where clause on table component

[lozdown]

I only want to show a table if $selector ='Visitors'. I have code which fails because of the where clause.

set SV='Visitors';
select 'table' as 'component', true as 'small', true as border, '' as empty_description where $selector=$SV;

Yet if I use the same construction on a button component the where clause works as I expect.

select 'button' as component, 'sm' as size, 'pill' as shape where $selector=$SV;

How can I disable the table component from displaying when certain conditions apply?

[lovasoa]

Hello !

It looks like you have a small syntax error in your first query. The correct syntax is:

set SV='Visitors';
select 'table' as component, true as small, true as border, '' as empty_description where $selector=$SV;

[lozdown]

I has not noticed my bad - Thank you

[lovasoa]

Quotes in sql

Single Quotes (')

• Used for string literals/text values
• Standard SQL compliant
• Used consistently across all major databases
• Example: SELECT * FROM users WHERE name = 'John'

Double Quotes (")

• Used for identifiers (table names, column names, etc.)
• Standard SQL compliant
• Allows you to use reserved words as identifiers
• Case-sensitive identifier names
• Example: SELECT "firstName" FROM "Users"

Unquoted Identifiers

• Default behavior for regular table/column names
• Usually converted to uppercase by the database engine (but depends on the database)
• Cannot contain spaces or special characters
• Cannot be SQL reserved words
• Example: SELECT first_name FROM users

Non-standard Behaviors

1. MySQL:

   • Uses backticks (`) for identifiers instead of double quotes by default
   • Treats double quotes like single quotes (for string literals) unless ANSI_QUOTES SQL mode is enabled

2. PostgreSQL:

   • Converts unquoted identifiers to lowercase (not uppercase)
   • Strictly follows SQL standard for quoted identifiers

3. SQL Server:

   • Uses square brackets [] as an alternative for quoting identifiers
   • Case-insensitive by default unless using a case-sensitive collation

Here's a comparison table:

Database	String Literals	Identifiers	Special Quoting Mechanisms	Example Query
PostgreSQL	' docs	" docs	$$ docs	SELECT name AS "First Name" FROM users
MySQL	' or " docs	` docs	" docs	SELECT name AS `First Name` FROM users
SQL Server	' docs	" docs	[] docs	SELECT name AS [First Name] FROM users
SQLite	' docs	" docs	[] docs	SELECT name AS "First Name" FROM users