>>>TEXT TO cSqlCommand TEXTMERGE NOSHOW
>>>	IF NOT exists (select COLUMN_NAME from INFORMATION_SCHEMA.columns where table_name = '<<tcTableName>>' and column_name = '<<tcFieldName>>' ) 
>>>		BEGIN
>>>			alter table <<tcTableName>> add <<tcFieldName>> <<tcFieldType>> not null default <<tuDefault>>
>>>			CREATE NONCLUSTERED INDEX <<tcIndexTag>> ON [dbo].[<<tcTableName>>] ([<<tcFieldName>>])
>>>	        SELECT CAST(1 AS bit) AS col_added
>>>	    END    
>>>	ELSE 
>>>		SELECT CAST(0 AS bit) AS col_added
>>>ENDTEXT
>>>

>>>
>>>But above I want the line CREATE NONCLUSTERED INDEX .. to be in the resulting cSqlCommand if the value tcIndexTag is not empty.
>>>
>>>How do I do it?
>>>
>>
>>

>><<iif(!empty(tcIndexTag),[CREATE NONCLUSTERED INDEX ]+tcIndexTag,[])>>
>>

>
>Thank you. I didn't know I could have nested

<< and >>

. I will try this approach.

You can't really nest merge brackets, because the parser will match the first opening one with the first closing one, and will then ignore (or be confused with) the unmatched one between them.

What I usually do when composing SQL is to create bits and pieces separately... IOW, something like this:

if empty(tcIndexTag)
   lcIndexClause=""
else
   lcIndexClause=textmerge("CREATE NONCLUSTERED INDEX <<tcIndexTag>> ON [dbo].[<<tcTableName>>] ([<<tcFieldName>>])")
endif
TEXT TO cSqlCommand TEXTMERGE NOSHOW
	IF NOT exists (select COLUMN_NAME from INFORMATION_SCHEMA.columns where table_name = '<<tcTableName>>' and column_name = '<<tcFieldName>>' ) 
		BEGIN
			alter table <<tcTableName>> add <<tcFieldName>> <<tcFieldType>> not null 
			default <<tuDefault>> <<lcIndexClause>>
	        SELECT CAST(1 AS bit) AS col_added
	    END    
	ELSE 
		SELECT CAST(0 AS bit) AS col_added
ENDTEXT