The more data that is read, the slower a query will become. It is a good habit to always specify which columns you need when you are writing your SELECT statements.

Example 1: Not the preferred way to do it

ARRAY TEXT(UserName_aT;0) BEGIN SQL     SELECT *     FROM user     WHERE user_id = 1     INTO :UserName_aT; END SQL $Msg_T:= "Welcome "+UserName_aT{1}

Example 2: A more effecient way to do it

C_TEXT(UserName_T) BEGIN SQL     SELECT userName     FROM user     WHERE user_id = 1     INTO :UserName_T; END SQL $Msg_T:= "Welcome "+UserName_T

The performance difference is more significant with larger returned data sets.