It is difficult to change the column data-type character varying to integer in running database, but need to query the string. Suppose we have a table which column Cal_1 has integer value as string, in PostgreSQL statement like Col_1>100 not return the appropriate data.
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Using typecast you can resolve this (Character Varying data type column with integer value) issue.
WHERE Col_1::INTEGER > int value
For the example we have the following table
CREATETABLEemployee ( IDSerialNOTNULL, first_nameCHARACTERVARYING(100), last_nameCHARACTERVARYING(100), salaryCHARACTERVARYING(10) ); --insert some records INSERTINTOemployee(first_name,last_name,salary)VALUES('Dilip','Singh','25000'); INSERTINTOemployee(first_name,last_name,salary)VALUES('Asish','Pratap','20000'); INSERTINTOemployee(first_name,last_name,salary)VALUES('Naina','Singh','200000'); INSERTINTOemployee(first_name,last_name,salary)VALUES('Mamta','Singh','10000'); |
If you will run the following query it will not return the appropriate data
SELECT*FROMemployeewheresalary>'25000' |
Result:
After typecasting of salary in integer (see the below query)
SELECT*FROMemployeewheresalary::INTEGER>25000 |
Result:
