Single Quote In A String

Hi,

i am trying to add a single quote to a string. This is a must because i am making a full select statement in which i need the single quote to compare values. Obviously this breaks my string invalidating my query.

ej:

SELECT avg(tabla.ip_trend_value) as valor, FLOOR(Cast(tabla.ip_trend_time AS FLOAT)) as tiempo
FROM TESTLAB5.dbo.CE02_L21_916AI31_43 tabla, TESTLAB5.dbo.CE02_L21_916XI31_4 t2
WHERE t2.ip_trend_value = 'Alimentacion Digestores' and t2.ip_trend_time = tabla.ip_trend_time
group by FLOOR(Cast(tabla.ip_trend_time AS FLOAT))

and this will become something like this.

SELECT @TableName = 'TESTLAB5.dbo.'+@TableName
SELECT @SQL = 'SELECT avg(tabla.ip_trend_value), FLOOR(Cast(tabla.ip_trend_time AS FLOAT)) FROM '
SELECT @SQL = @SQL + @TableName
SELECT @SQL = @SQL + ' tabla, TESTLAB5.dbo.CE02_L21_916XI31_4 t2'
SELECT @SQL = @SQL + ' WHERE t2.ip_trend_value = '@NombreVar'and t2.ip_trend_time = tabla.ip_trend_time'
SELECT @SQL = @SQL + ' group by FLOOR(Cast(ip_trend_time AS FLOAT))'

the @NombreVar is the equivalence of 'Alimentacion Digestores'.

is there something i can add or change to make it work ?