Invalid SQL statement for Text columns lookup

Question

I'm working in ArcGIS Pro and writing rows from a source file with Text data type field to another text field in a target file but it generates an error as such:

An invalid SQL statement was used. [SELECT unique_id2, Col2, OID FROM fc2 WHERE unique_id2 is equal to 274162].

*note 274162 is the first value of unique_id1 which is also present in unique_id2. Below is my script:

with arcpy.da.SearchCursor(fc1, ["unique_id1","Col1"]) as cursor:
    for row in cursor:
        SQL_stat = "unique_id2 is equal to " +str(row[0])
        with arcpy.da.UpdateCursor(fc2, ["unique_id2", "Col2"], SQL_stat) as cursor1: #Error
            for row1 in cursor1

My code works if the fields are Integer and not texts, but I need to work with text fields. Also a print statement of the SQL_stat prints out the WHERE clause as it ought to

Answer 1

Try using AddFieldDelimiters and format to create the sql expression string:

SQL_stat = "{0} is equal to '{1}'".format(arcpy.AddFieldDelimiters(datasource=fc2, field="unique_id2"), row[0])

Not sure how your data looks like, but you should probably think about using a dictionary instead of nesting cursors. Something like:

datalookup = {k:v for k,v in arcpy.da.SearchCursor(fc1, ["unique_id1","Col1"])}

with arcpy.da.UpdateCursor(fc2, ["unique_id2", "Col2"]) as cursor:
    if row[0] in datalookup:
        row[1] = datalookup[row[0]]
        cursor.updateRow(row)